stomach and vomiting

well i am a 22 year old male and for about three years i have been expericing bouts of vomiting. when i do have an episode they last for about a whole week if not two weeks. for the whole week or two i feel constant nausea and discomfort. i throw up so much by day 2 i need to be hospitalized because i am so dehydrated but yet i still vomit for days. i have been to several doctors and specialists for the stomach but none of the doctors have found anything wrong with my gut. they say it is healthy. i have even had a colonoscopy to see if i had something wrong in there and it was healthy too. the doctors here dont know what else to do for me anymore because i get this way almost every month and they feel like they really dont know what could be causing this. when i get sick my hands and face also go numb. they are not always numb but just out of the blue i will start feeling some kind of tingling like when your arm goes to sleep. i also feel bloated alot and sometimes it is so bad and i cant pass it. this last time i was sick i lost about 15 pounds in 3 days. i feel so awful that i feel like i might not make it if this is something that i am going to have to learn to deal with. throwing up a week straight out of every month i know is not good for me or my health. the doctors say they have tested all of my organs to make sure none of them are causing this and all the tests came back negative. they have done a scope down my throat like 10 times and still found nothing. i have had an ex-ray and an ultra sound on my stomach and still nothing. when i get sick i feel so miserable and weak and i cant even hold down a sip of anything to drink. because if i do drink something it will come right back up. i know this is not a good thing to have been going on for over 3 years and i hope someone will reply. also here is an e-mail address to contact me at. _[removed]_.