I felt this way after my first child was born and he was a toddler about 6 years ago. I had been a very outgoing, bubbly, happy woman. When I became a mom I thought I sucked at everything dealing with my son. My husband even mentioned why I wasn't having fun and taking care of yself. Honestly what helped for me was going on wellbutrin for about 6 months. After that I started working out religiously and joined a city league for othe rmoms to play basketball, volleyball, and softball. After that I was fine.
After my second was born I noticed those same feelings again. But this time no wellbutrin, just tried to give it a go and see if things went back to 'normal'. I don't think it wil, you just gotta make things a priority, namely yourself. Find something that you enjoy outside of 'momdom'.
Try to get along time with your hubby, get a babysitter to helpwith this.
Are you taking care of yourself? As in getting up and getting dressed/makeup/hair done? I find when I don't do these things I feel really bad an dfocus on all that during the day. But when I do get a little dressed and look pretty I feel good even aobut spending 5 minutes reading to my girl.
Good luck, it is hard, just keep your head up.