Need some advice with jealousy towards my girl.?

aight so i been goin out with my girlfriend for about 2months now, n shes the best thing thats ever happend to me. im only 17 years old btw n so is she. so heres how it is, shes really popular n i used to be ever since we started datin i kinda lost most of my good friends, n so did she. she has alot of guy friends everywhereee girls aswell, but mainly guys. everytime we go out she always sees em i dont get jealous of that, well some guys i do get jealous of. but mainly i get jealous when she wants to go out on a friday night or saturday whatever with her girlfriends to a party or somethin, n when i find out its like i dno, i feel really jealous but kinda upset in a way, because 1. shes goin to a party drinking or like to the city for late night n shes gonna meet up with guys aswell, coz her friends are single so they wana mingle. to be honoust i dont want her to go because of the guys n i dont really get along with some of her girlfriends n theyre the types that jus go out looking for guys to talk to n whatever 2. i jus get really jealous when she talks to guys whether it be facebook or in person, i hate this feeling...... it makes me feel like ****. i do trust her but i dno i always have doubts. deep down inside im sayin to myself, what if. i dont want to tell her "no your not going out tonight partying" coz i mean what kind of boyfriend does that.. i dont really hang out with my friends coz im always with her, plus i dont really have many friends... i know its kinda sad but i lost them. what do u think i should do to handle the jealousy issue? thanks alot!