From Longman Dictionary of Contemporary Englishsinking feelingsinking feelinginformalHOPE# the unpleasant feeling that you get when you suddenly realize that something bad is going to happen I had a sinking feeling inside as I realized I was going to fail yet again. → sink
Examples from the Corpus
had ... sinking feeling• And Dot had a sinking feeling because she realized she'd known all along even though she hadn't wanted to. 