Maybe ask for it to be increased just a little bit further. If there are really indications you might become manic.

Lamotrigine can at first cause mania, but generally only at a dosage of 100 mg daily, maybe 75, any lower dosage may have a slight effect though, and shorter than you may ever have experienced. It will probably stabilise you soon after. May be just a few days.

Hope you don't get any side-effects from either.