Why do I feel so bad about my aunt telling me that I'm fat?

I am a 31 year old single guy. I'm 6'2" tall and have always been really skinny. I admit that I've put on a few pounds in the last few years and I have filled out some. I also have a little belly and love handles and I'm getting man boobs and my face and neck have filled out some. But I never really thought of myself as fat. Until yesterday. I met up with my aunt and uncle, whom I have not seen in over 6 years, and, as I walked up to them, my aunt blurted out, "OH MY GOD!!! ---- GOT FAT!!!". Ever since that moment I have been really self conscious. I now hate looking at myself in the mirror. I haven't eaten anything all day because I don't want to eat anymore. I feel so bad about my looks now. I don't know what to do. I feel so depressed now.