so my left gland is swollen under my chin . it s very sore. I ve been sweating a lot and been feeling very dizzy. I don t have a sore throat or a cold, my mouth seems fine and i recently went to the dentist , i don t really share drinks or anything so i doubt i have mono, no skin or ear infections that i can tell, and i for sure don t have an STD i m a virgin . what could this be from?? is it serious?