Social Event coming up, huge anxiety about attending

I felt I needed to post about this as I know many of you go through the same sort of issues all the time. I need help in figuring how to navigate this situation and maybe support and reassurance. Also, this might be a question that others are facing themselves right now and want to know what to do, so hopefully this can help some people out there.

I have an engagement party coming, one of my best friends is getting married and the invite came out this week. It's on March 12th. Many people have seen me at around the 215lbs mark and do know I've gained quite a bit of weight over the years. But at the moment I'm struggling to get out of the 250's. There are also some people in his family and friends that will not have seen me in 10 years due to me being away at college and off social media and will not have seen me since I was in the 170-180 region around 2013.

I now know that BED has consumed my life. All I think about is dieting, calorie restriction and I know that that causes me to binge hard if and when I eventually cave in. So I'm currently in that destructive loop and I'm having a real struggle getting out of it right now. I have promised myself to get out of the 200's by the end of this year and although I have plenty of time to be chipping away at that goal, I don't have much time at all before this party. I don't know what to do. Part of me is just saying suck it up, lose what you can realistically for the month, but attend for your friend..people will notice, most won't really care and the night will pass like any other night will. But there is a part of me is thinking run, hide, avoid.. typical BED behaviour. Tell your friend that your social anxiety is through the roof because of this disorder and you can't attend. He would be surprised to hear I'm going through so much stress over this and would tell me to relax and don't worry about showing up, I know he would. The final option is the worst one and the one I've been using when I don't really care about the people as much and that is lie, just say you can't make it. But this would almost be like lying to family and I'd love to either attend or be honest about my problem and let him know I can't attend because of that. Both are wins and losses for different reasons.

Any ideas guys? The larger problem is of course my disorder, I need to get out of this hole this year. But the lesser, more immediate problem is facing this party as who I am now, or not facing at all. Any help?