What Causes Swelling And Itching On The Lips Of Vagina?

HI I'm an 18 year old female. A few months ago I was very sick and out of no where I started getting very itchy and I got swollen the next day that went away about 2 months later I woke up with a swollen lip a went to get benadryl because I thought it was allergys the benadryl seemed to help I was sitting down watching t.v. And all of a sudden I got really dizzy I could hear my heart beating fast and everything got blurry I felt like I was going to faint and I felt like I couldn't breath I sat down because I was weak I couldn't stand up on my own I was extremely shakey I thought maybe it was the benadryl so I fell asleep for hours and ate something and that seemed to help but then 2 weeks ago I was at the movie theatre I was sitting down and I felt my lip get swollen I didn't pay any attention to it then I started getting dizzy like I was going to pass out and tingly I got hot and cold and short of breath again I culdnt walk I was very shaky basically the way I felt that other time but this time I felt my throat closing up and it was getting harder and harder to breath I felt sick all night feelin like I needed to vomit the next day I went to the hospital they told me I was hyperventilating because I was breathing fast but today I was sitting down watching t.v again and I felt the same way but not as bad as last time I got better but I was shaky all day & I felt pressure on my chest and feeling like I was going to vomit and short of breath all those symptoms come and go I feel better one minute and then I feel sick again I Dont know what to do the doctors tell me I have nothing wrong with me but I don't understand why I feel so sick?