I've been taking Lamictal for close to 5 years now and am up to 400mg/day. At first I had a sense of euphoria but it may have been a combination of lamictal and gabapentin. Gaba tends to give me a false sense of mania/ hyper excitability if I take my full dose during the day. Otherwise it's been extremely effective in helping maintain a slight stabilization in my mood shifts and with my increased dose actually has a sedative effect.

I agree with Christina as well. The sporadic spending and tattoos sound a lot like mania. I've found myself in a manic/hypo state when my medications have been slightly shifted and it's quite possibly from anticipation/over expectations of a sudden effect and change.

I would just keep track of the trend in things you are doing that you usually may not and let your p-doc know. In the past I've done this and my p-doc was the one who recognized the mania pattern.