Hi LoveHopeStrength. Don't punish yourself! We all relapse. I can't tell you how many times I had to pick myself up, clean myself off and say "well, I can TRY to make that the last time". That's all you can do-try your hardest. The guilt and the shame are only going to keep you in the cycle. Be gentle with yourself. Try to use different banter in your head like "well THAT happened and it might not be the last time but I am not giving up". Slip ups happen to everyone. That's why I don't like to count how many days it's been since I purged. It's a recipe for guilt if you have to go back to day 1. And who needs more guilt! You slip up, you pick yourself up, you try again.
What I'm really concerned about here is you are on Wellbutrin and Wellbutrin lowers the seizure threshold for bulimics. Like, A LOT. That's why you have to tell your prescribing doctor. Bulimics are at risk for having seizures anyway but along with the Wellbutrin the risk is so high my p-doc took me off immediately when he found out I was back to purging (a while back, I've since stopped with the help of another med). So please, tell your doctors. I know it sounds like the hardest thing in the world to do but I don't think you should go cold turkey off Wellbutrin either. You should be taking something for the urges and anxiety.
Does your boyfriend know about the b/p? Men will NEVER understand why we do it and sometimes I regret telling my husband (he still makes me pee with the door open

) but he was a big help when I was in the thick of it. He followed me around for two hours after every meal to make sure I wasn't purging (I asked him to do this) and that helped my stomach readjust huge.
I hope some of all of this helps!!