Kiisha, Can I say that being a Mum is the hardest job in the world and is so highly valued by society but they don't show it. Society focuses on the failures, the trouble makers but if you can have a family and rais several independent, well balanced young people you will achive more for the world than any job could. Truly, I do believe that so much. So please don't put yourself down for wanting that, it's actually how your body was designed, to want and have and care for children. May be a sexist thing to say but I can't fight biology of millions of years.
You talk a lot about all the things you want to do and then basically you say "But I can't", or "It's catch 22". That's because your are thinking of things your mind right now is telling you that you can't do. Of course, you can when you are not depressed or whatever it is you are feeling. Could I suggest you need to refocus away from what you want to what you need so you may get what you want. That just means I think you should make solving the misery stuff is your first priority. You haven't lost any ability, if it is depression then what you describe is exactly how it works. It takes away your interest and reasons for doing anything so you feel useless. Which, if you look back, you are not. Seek help, treatment and you will get what yuou want if you try hard enough to make it work.