1. supplementing with a very high quality probiotic ( the kind that needs refrigeration) since you were on Antibiotics , your gut flora is probably out of balance which has a ripple effect on the entirety of your body and mind.
2. Do you take an omega 3 supplement? If not, you should as your omega 3-6 balance is probably off, I would recommend a dha kind over EPA as dha is better utillized in the body.
3. If your thyroid is out of whack you may be gluten intolerant, try cutting it out of your diet for a month and see if you feel better. Also supplement with iodine, no megadoses though!
Try the things the first person recommended too, but these should address many of the psychological issues... I know from personal experience. Liver flushing/colon cleansing with Bentonite clay re both good ideas.
Also might try a parasite cleanse as I'm not sure of the effectiveness of Antibiotics in treating parasites.