Hon, you have every right to be upset and ****ed off, not only did your SIL but your friend I take it did thid to you but everyone else now has put the focus on her.
It's not your fault that she's smoking, but you can bet your bottom dollar that in the next mths, she'll be preggers too. (sorry if I have her wrong)!

If you really feel that you can talk to her then try, all you wanted was a congrats from her I assume not a massive deal made out of it.

Well Im happy for you and Im sure hopefully you can sort it all out. Good Luck sweetie.xx

PS what did DH say/do?