Why do I cough up foam at night?

Every night since I have been home (4 nights) I have not been able to sleep because of the coughing attacks. Tonight, I coughed up foam, twice. This concerns me, and is exasperating. Sleep is so evasive for me. Any help out there? Kay

We greatly appreciate your interest in helping us build our Q&A database. To discourage vandals from posting garbage, however, we require people to register before posting.