2 week old throwing up foam?

My cat had kittens two weeks ago which I dont even know how it happened since my male is fixed.. but anyways last week the oldest kitten was crying real loud so I checked up on her and she was throwing up some clear vomit.. Well last night and today she has been throwing up thick white foam that also comes through her nose and when she cries it doesnt sound like a normal kitten cry it sounds like she is in lots of pain, almost like a death cry.. After a while she seems normal and the three other kittens seem to be fine.. Has anyone heard of this and/or know what could be causing her to throw up foam? ..Is this normal for small kittens or does it sound like something more serious that the vet should look into?.. Please help!

If you even think of bringing them to a vet that is your answer... a vet is required.

If your female got outside even once, even for a few minutes, that's how it happened. Cats are very fertile.

Anyway, it's definitely NOT normal for kittens that age to throw up at all. And especially if they're crying and having stuff come out of their nose. She needs to see a vet, and fast. They go downhill so quickly at that age. Keep us posted about what the vet says!