Stopped taking my anti-depressants?

ok um i take bupropion hydrochloride SR in 150 mg tablets twice a day.its a anti-depressant that is supposed to help with major depressive dissorder. i flushed the entire bottle of them this morning because i was frustrated and i thought it wasnt helping. and i know im gonna crash [go back to being depressed] i just want to know when and how hard.. cause i heard that if you take anti-depressants and you stop then your depression comes back alot worse. i dont want this to happen. so im kind of worried. so is it going to be bad?