Sounds like my 18 month old some days. Is he bored maybe? Does he get enough sleep?
Would you be willing to try a mothers day out or part time daycare? Ds has honestly been a much happier child since starting daycare. Not sure what that says about me as a mother lol, but he just loves the interaction with other kids and being kept busy with fun activities.
Also, is there a chance your antidepressant may be affecting his mood? Or any any allergy medication?
Anyways....I wish you all the best because I know how frustrating it can be.