This sounds like straight-up depression and I hate that you are questioning your medication and your GP. I understand entirely, but I hate that you're at that point of doubt whereby thing don't make sense as it's so distressing and I can really understand.
I've been on antidepressants for six years. I'm 26 and came off them a while ago which was horrendous, so I'm back on them. After trying out a lot of therapies and medication, the best tactic I've adopted is to question the hell out of everything. When my GP prescribed something new years ago, I wanted to know *everything*. The history of the drug, side effects, the success rate...and you should know that. If you're taking a pill, you should know what the background is!
Honestly, prior to me finding the right pill, I couldn't get out of bed, let alone prepare food, shower, work etc. Keep trying and keep communicating.