One of the rare side effects of Wellbutrin is abnormal dreams. You might want to talk to your doctor about discontinuing it to see if the dreams stop.
Did they ask you for a script? Typically, legit pharmacies require a script.
The "more information" tab says it's Eltroxin, which is a Synthroid equivalent in many parts of the world. In another section, it says it's "generic" Synthroid, which is a contradiction in terms.
Each manufacturer uses different fillers, inactive ingredients in their tablets. Some of us are sensitive to those.
You're not taking B vitamins, are you?