I think you should give yourself a designated time period for you to actively mourn. Like maybe 3-4 days. Then you have to try and not cry after that because if you do it will make it harder to get over.

Since it was your first real relationship, there are going to be problems. It's like you're just exploring that part of yourself and you don't know how to react in every situation. I've been dating the same guy for a long period of time and we still have communication hiccups. It's a normal part of life. That's why therapy will help YOU. It seems impossible, but the next time you get into a relationship, YOU will have the skills to communicate in a non-defensive way and hopefully the next girl you are with is willing to learn from you. You can also ask your therapist to teach you about having healthy boundaries.

A relationship will never be perfect and it takes two to make it work. I don't think you should feel guilty about the failure of the relationship. It sounds like YOU tried to do the best in your own capabilities. You may have been more demanding of her to move forward, and maybe she wasn't ready to take that step.