Sweetie, I wish I had a magical solution for you. I'm the queen of mental blocks... I spend a whole lot of time thinking, "Augh! Why can't I do anything??" I read your post and thought, "Hmmm... Did I write that?" I'm very motivated and competent at work, but I still struggle with procrastination (a lot) when I'm at home. My long-standing mental block is -- "Augh!!! Why can't I clean up my flat??"
Therapy can help. You just need to give it a chance. I wish you had started it sooner too, but it's good that you're considering it now. Then, a few months from now you can think, "Wow, I'm glad I started therapy when I did!" I used to have mental blocks stopping me from leaving my flat. My anxiety was so out of control, I couldn't even step outside on my deck without freaking, and therapy and meds helped me get SO much better.
Don't feel bad about venting on the forum. That's what this forum is for. Talking about this stuff and getting it all out is healthy. I always feel like I should be happier than I am too, but I'm not. I have problems with depression and anxiety and those things are diseases that skew my perception. There's no need to feel guilty about having an illness. It's not my fault that I am the way I am and it's not your fault that you are the way you are. We're not weak or bad or selfish. We're fighting illnesses here. The brain is just another organ in the body and there's no shame in having an illness that affects the way our brains work. The important thing is that you're reaching out for help and trying to get healthier and happier.
Hang in there. I know it's tough. You have SO much going for you. Once you get into therapy and put all your insight and intelligence into working on your therapy, you'll be amazed by what you can accomplish.