self conscious

So I have family in town and they want to go to the beach and I used to love the beach until I gained a few pounds and my hubby wants to go to but I feel so self conscious to be in a bathing suit anymore and the bathing suit bottoms don't even fit me anymore and I haven't felt up to buying a new one that fits. my sister will be going and she is in great shape I just want to avoid going to the beach now so bad.