Lamotrigine and BC

Zara • 27. MN.
I'm on the mood stabilizer lamotrigine for my mental illness and norethindrone (BC) for my menorrhagia. My menorrhagia was getting much better, but I've noticed over the last couple months I've started bleeding more heavily again since starting BC. This seems to coincide with my increases in lamotrigine. I just got bumped up to 200mg/daily lamotrigine. I am not concerned about pregnancy since I have a copper IUD. Anyone else ever experience this? The only side effect of both drugs I had is when I started BC AFTER being on lamotrigine, I needed to increase my dose because my mental illness symptoms worsened. But this is the opposite- now I'm looking at the possibility of my lamotrigine affecting my BC and making it less effective. Thoughts? I can't be on SSRI's. If HAS to be a mood stabilizer and I HAVE to be on BC.