Whether or not your therapist believes you is not why you should or should not tell her. She is not there to judge you, she is there to help you no matter what problems you have. If she is not doing that, it may be time to either talk to her about that or find someone new to see.
The only way you are going to feel better is if you move forward. If that takes one day at a time or even one moment at a time, it's worth it. Staying as you are now and not trying to move ahead is only going to keep you feeling bad. You may have more than your fair share of bad things happen, but if you don't get back up and try, you will only give up and that won't help anyone, particularly your daughter who needs you.