How can I lose 20 pounds fast please help?

How can I lose 20 pounds fast before summer is over preferably I’m moving back to my hometown in a few months and i don’t want to feel embarrassed because I’ve gained 20 pounds and I want it off before I move back and see my friends. No I’m not doing it just for that reason I also want to be healthier but it is a motivator for me. I have PCOS and I’m almost always on my period I get it every two weeks so weight loss is super hard for me. People with PCOS what are some tips for me to drop 20 pounds? Thanks!