Is Zoloft a methamphetamine

In short, no.

The two are not chemically related and amphetamines work primarily on nerve receptors that are naturally triggered by adrenaline/ephinephrine (two names for the same chemical) while Wellbutrin works mainly on a neurotransmitter called Dopamine.

That is a simple answer, in truth psychopharmacology is much more complex. You should always consult your physician or a psychiatrist before taking either.