It sounds like you have a very healthy perspective on this. You understand why she is behaving the way she is, and you want to be there for her, but you're right - all humans have their limits. It's very kind of you to be a listening ear for her, but you do not need to do that at your own expense. It may be helpful for you to establish some boundaries with her. She may not be in a good place to hear your needs, so she may not react in a healthy way, but you could try to approach the situation gently and just tell her that you value her as a person and you care about her problems but that sometimes you need a break to focus on your own struggles. If she does react poorly, just give her some space. Sometimes it's good for people who are struggling to see that their problems are not the whole world, other people struggle too and you can help each other through it together without comparing notes on who has it worse. Good luck. <3