dortie145, you have no need to feel guilty. You are, in fact, very lucky to have an elderly parent who is still well enough to take care of herself. There may come a time when she does need more help, and that will be the time to do whatever you're able to do for her.
I've spent several months at a time staying in my parent's home, when my mother was ill, before she passed away. And then again with my father due to illness/operations/recovery. Quite honestly, as much as I love him, I could never, ever, live with him permanently. We would drive each other insane!
As Hetty 58 said, you need your own space, and I'm sure your mother does too. We all get set in our ways as we get older, and we have our own routines, which are disrupted when you have someone else living under your roof. Much better to live separately, and be able to offer help when required.
I'm sorry for your circumstances, that it was necessary for you to move back in with your mother, and hope that things will improve for you. Thank your mother for all the help and support she has given you, but tell her you feel it's time that you moved out, so you can both have your own space again. Hopefully, your relationship with each other will then improve.