Jennifer, replace 'codependent' with 'highly empathetic' & 'protective' (both admirable qualities), and I think you'll have a much more accurate characterization of what you're experiencing. That being said, I do understand how empathetic feelings can be experienced in a manner which is overwhelming and destabilizing to your state of being. This is why it's important to gradually develop a stronger foundation of your 'sense of self' and with this comes firmer boundaries and the ability to bounce back to your base state of being much more quickly after any type of emotional disturbance. This will come about over time and continued (inner) work. Empathy is best utilized in a context where you have the ability to take some form of meaningful action in response to the circumstances which generated those feelings. When we experience empathetic feelings in circumstances where we cannot respond and act in a functional & meaningful way - this tends to yield feelings of helplessness & powerlessness. I think important to catch yourself in the experience and then ask yourself if there is any action you can take at that very moment to do anything constructive - and if the answer is "Not right now", then this realization and acknowledgement can encourage you to 'pull back' and detach/disconnect from that empathetic emotional state for the time being. Does that make sense?

As far as your circumstances are concerned - I would recommend some of the following mental practices to promote a heightened state of awareness, which will benefit both you & your daughter:

1) Instead of internalizing your daughter's emotional states and feeling troubled by your perception of her current external life circumstances - you have to steer yourself towards consciously connecting with the bigger picture that's in play. You have to work to increasingly broaden your perception/perspective of these matters. Kinda like you're zooming out and seeing everything from an ever higher perspective than you had in the past. Spend time contemplating what it was like when you were around her age range. Didn't you endure through challenging emotional states and certain hardships during your younger years? Didn't you observe other friends and peers going through their own challenges & hardships and enduring through them much the same? Can't we say that going through such experiences is a very common and natural aspect of the human experience? She's not alone in what she is going through and you are not alone in what you are experiencing. Many many others out there who have either already had similar experiences, are currently having similar experiences, or will later endure through similar experiences. All this is not abnormal nor unnatural by any means. I think it would be really important to engage with your daughter in a manner that promotes/encourages/fosters this awareness & perception of what she's going through as being a natural part of the human experience and something she's not alone in experiencing because others have gone through this as well. Perhaps you can identify some parallels between either yours or other family members life expeiences and make a connection to what your daughter is dealing with - then ideally you could have such a conversation with your daughter and I think it would be good for her to learn more about some of the challenges/hardships that her Mom or other relatives have navigated their way through and endured through. Or even if you can't identify any parallels, you absolutely could open up and speak to your daughter about some of your more challenging life experiences and describe the nature of how you felt at the time, describe how you pulled yourself through those circumstances, and how you ultimately experienced internal growth (refinement) as a result of having faced such challenges & adversity.

2) Very important to set aside time for contemplating the ways in which your daughter can learn valuable lessons and consciously evolve, and refine herself (her nature/character) as a result of being 'tested' and enduring through these challenges that present themselves during her life experience. Again it would be helpful if you can connect with examples of this unfolding within your own life. This will serve to increase your acceptance and understanding for what she is going through - and increased acceptance & understanding yields a strengthened mental/emotional state for you. Increasingly integrate the awareness & perception that your daughter, although struggling in the present, will ultimately discover genuine meaning and value from having pushed herself through the burdens and hardships that she faces during her lifetime. This will eventually happen when she develops the awareness to realize how she was subsequently 'changed' and refined as a result of what she went through - and this realization is for later on down the road of course... Also very natural for us to find ourselves looking back on past experiences in a new light and with the recognition that they served to contribute something very meaningful to our nature & state of consciousness. So yes, if you can get creative and really tap into your contemplative abilities - I know you'll be able to identify ways in which you'll perceive that she'll be able to grow and therefore benefit from having been tried/tested/challenged during her life experience in the way that we all are. There is a higher purpose behind this all and the more we can tap into that awareness, the more we become liberated...

3) Lastly, analogies and metaphors can be extremely helpful for individuals to connect with when they are struggling to understand what life has presented them with. Again, work to identify some appropriate analogies/metaphors that you can express to your daughter and if she can make that connection it will serve to encourage her to gradually perceive her life circumstances in a different (new) light and this will prove to have a positive effect on her emotional states...

Regards,
~wolfgaze