The skin under my boobs is flaking off and the area around my nipple is getting darker and my boobs are getting bigger. we had sec and we had a condom?

Do pregnancy test: after the date you expect your period. Darkening nipples and breast enlargement can be signs of pregnancy. On the other hand, if you used the condom correctly and it didn't break, it can be up to 90% effective in preventing pregnancy. Consider more reliable forms of contraception in the future, either the pill or implant, but continue condoms, too, for STI prevention. Best wishes!

Dark areola: increasing breast size, darkening areola can be sign of pregnancy, if worried, have a pregnancy test

Pregnancy: I'm thinking you need to rule out a pregnancy with some of these changes. Although, the flaky nipple changes don't fit the picture. This may be a whole different matter (e.g. infection, non-endocrine skin changes, etc...). Get it checked out. Good luck!

Many things: There are several conditions that can cause the symptoms that you described. Although some may be benign, there are others that should be treated. I suggest you see your primary care doctor as soon as these symptoms appear.

Do a pregnancy test: You may be pregnant in spite of the condom as it fails when used alone 20% of the time. Do a pregnancy test.