Im 15, and ive been dating this girl for 5 months. We have known eachother for a couple years already, and dated once when i was 12. We have been having sex for 4-5 months already so im not shy about it with her. were both perfectly comfortable with sex. the problem is i cant get a boner as much i did. (I used to get them all the time, but this last 2-3 weeks ti has been lacking) and when it does happen , its soft and usually goes away quickly. Dont get me wrong shes beautiful, it isnt her. What could it be? could it be stress? anxiety? Im not fat, have diabetes or smoke cigarettes, although i did use to smoke weed and take concerta.. but i dont think that has any effect. could it be ED? even at 15? Im really worried.. i dont know what it is. By the way, i recently got expelled for fighting 2 kids . i was protecting 4 of my freinds. Im away from all my freinds and my gf and in a new school. could that be the problem? im really worried. anything will be appreciated. please help.