Not the end of the world but yeh it will likely suck in most conditions. Sizing varies with style, board, and rider.
I used to be 190lbs and rode a 160. I'm down to 160lbs these days and ride a 156. I freeride more and the sizes work for me. My rotund buddy is 240lbs and rides a 160 quite nimbly in most conditions.
At least you have something for something for powder I guess but there's mostly skill and technique involved in that area. If you don't see yourself gaining another 50 lbs then it won't be fun with such a big board. It'll feel like a plank.