It'll depend on a few things. What dosage of zoloft are you on, for how long? How much valium have you been prescribed and for how long?
Weaning off zoloft I was given valium to help ease me through it. The problem being I took the valium but didn't have the mental withdrawal (only the physical) in the first 2 weeks. So I'd stopped the valium and then I got hit with major mental withdrawal, but then I'm prone to suffering bad withdrawals off any med.
50 is the lowest effective dose of zoloft, the big question is, did it help you? if not, maybe up the dose
I doubt a psychiatrist will help much, they are expensive with usually a long wait for the first appointment
valium and zoloft are often taken together and valium would make it easier to stop the zoloft