What Causes Excessive Salivation And Foamy Spit?

Hi about a week ago i was very ill with a sore throat. i took some meds and the sore throat cleared up but i have been left with excessive saliva, lower stomach discomfort, and fatigue. I keep havin the urge to spit and when I do the spit is kinda foamy . What is this any idea. Also i recently discontinued my birth control and have been waiting for my period for over a month. Im not pregnate