Being the "big" girl...

I have this issue where I'm really big in one or two places. I struggle to feel confident in a bikini because I have a large tummy and unfortunately it makes me look pregnant. Me and my boyfriend went on holiday about a month ago and while we were away I genuinely had people come up to me and ask how far I was. I felt so shitty I'd either pretend I didn't understand the language or I'd go along with it. I am a U.K. Size 14-16 depending on what the item of clothes is. I have a best friend who I love with all my heart who is a U.K. Size 6. Shopping with her kills me because she will literally turn around and say nothing fits her right and she needs the next size down. I know her body is unhealthy as she's a recovering anorexic but all through life I've surrounded myself with "skinny" friends. I have put in three stone in the past couple of years and I'm really struggling to find something to like about myself now. I just want to know who else feels like the "fat" friend who just exists to make everyone feel better about themselves? 😪
[p.s. It's probably best to note I am on my period and I have just watched this pretty sad puppy rescue show and I am just SO emotional right now 😅]