You can get B12 sublingual and B-multi (maybe in liquid form)
You should see an immediate improvement in you energy level, and perhaps you mood.
As I understand it, due to a number of possible reasons, we may not be absorbing the B's and they are essential for energy and serotonin production. Some are manufactured by friendly bacteria that we may be lacking due to Antibiotic exposure.
Drink lots of water, (I would tell you with celtic Sea Salt & lemon if possible.)
This should at least get you enough energy to start figuring out what you'll be doing next to regain your health.
Feeling like you cannot even complete one task is daunting. I hope the B-12 can at least help you on your first step...