Debora,
Thanks for your question.
If you think your relationship is tanking, talk to your boyfriend and try to work things out. If you can't, don't panic. It might be the right time to let him walk out this door.
or
And my love life was tanking, and today was fish sticks day, and I hadn’t finished my French homework, and I just knew Ms. Beauchard was going to call me on it.
http://www.ebook2u.org/book2/The_Winnie_Years_5/index_6.html
fail; do poorly.