It sounds to me from what you have shared is that your life has been mostly about giving up a lot of control to your ex and spending most of your time raising your children. It's simply what you know HOW to do. Making friends and feeling free to just be yourself is alien to you right now. It's pretty normal considering what you have shared. You probably were alone a lot before when you were married and busy raising your children, you just didn't realize it the way you are now.

I think it's a good start that you have gone back to school to get your masters. It's high time that you did something for yourself like this. Give yourself some time to adjust more to embracing yourself, remember that this really isn't something you ever really did for pretty much most of your life. You really don't have to be in a relationship with someone else, it's really OK to develop a relationship with yourself and finally develop your own personal identity. It sounds from what you shared that you got good at being a codependent unknowingly.

It's actually not a crime if you decide you don't want to commit to another relationship. Give yourself time to slowly work away on yourself and get your degree and then use that degree FOR YOURSELF.