While its possible Lamictal could cause depression altho I have never of anyone that happening to.

Lamictal works just on the depressive end of Bipolar. Yes they have now classed it as a mood stabilizer the medication is actual for Seizures

Quitting more than one med at a time typical has people crash and burn,

Unless a Doctor advises stopping numerous ones The best way to manage it more safely and easier is too determine what the half life of a medication is and then cut in half IF its a med that can be split, Then stay on that a couple weeks, The go every other day for a few weeks then cut to every 3 days ..

All that said I am NOT a Doctor of course. But stopping one medication at a time and going slow gives you the best chance of not throwing yourself into hell.