Bulimic symptoms and conditions

I have been on Lamictal for about 3 and a half yrs now for Bipolar 1. Overall, I have had a really great experience with the drug. I started with 100mg and then went to 200mg after a year and a half. Now I take 225mg as of a month ago. For about a year and a half I had the acne on my chin and then it went away suddenly (thought it was cutting out dairy from my diet though). I have been extremely fatigued for awhile now. 7hrs of sleep is not good enough for me so I end up taking long naps when I have the opportunity each day- I always want to sleep. I feel stupid and lack focus and motivation. I use to be a social butterfly and now I feel so exhausted when entertaining. I am a personal trainer and am in the business of making others feel better, but I seem to be feeling worse. I have experienced weight gain as well and that is hard for me since I use to be bulimic and have always had poor body image issues. I was on the NuvaRing for 5 months and it made me sooooo depressed so I finally got off that and feel better- don't mix those 2 drugs.
I am going to ask my doctor to take me off of it this week because I am ready to trust God with my mental health. I have a great support system to help me through the tough times and if I want to get pregnant, I have to go off it anyway.

Does anyone know how vomiting can lessen or negate the effects of birth control? I've been bulimic for years and didn't know if that would cause the birth control to not work. It's not as bad as it used to be, but I still worry. Anyone know anything about this? Thanks.

Molly