Congratulations on three weeks! If you can do it for 21 days, you can do it for one more collection of 24 hours. And that's all you need to do. When you say "I still feel like crap" are you talking about physically or spiritually? If you are feeling physically ill, go see your doctor and tell him/her. You have put your body through a tremendous amount of physical abuse.
If on the other hand, you are spiritually hurting, talk to somebody. What's got you feeling down? My experience is that specific things that make me feel like crap don't hold up well when I drag them out into the bright light. They need the company of other bad feelings to have any real power.
One thing I learned is that when I feel like crap, I feel like crap. So? Nobody ever told me that recovery was going to be magic or instant or easy. The hard part was learning to sit with the crappy feelings without picking up. As a very wise woman taught me "No matter what happens, your head WILL NOT explode and you WILL NOT fall off the face of the earth." To that I'd add "When you get to bed at night and the bed is not spinning, you just had a good day." No matter what else happened, if you didn't pick up you had a good day.
Jah Bless