Feeling like a loser?

So I'm 17 and me and my friends went camping last night and I really feel like a loser at the moment. All my friends were getting off with each other and I mean literally all of them except me and this other guy. I'm always seen as the friend It's the classic story but the thing is I don't even try to play the get to know really well then ask out game I just seem to be classed as friend straight away. I try to be sexy and I'm very quick witted and I'm a likeable guy but girls just don't seem to see me as a potential boyfriend. I'm not doing too great in my a levels, my dress sense is okay and I havn't got a job :/ I'm just feeling like an all round loser. I havn't had a girlfriend since christmas and I havn't even gone passed pulling whilst all my other friends have partners and are having sex etc :( I'm feeling really low at the moment has anyone got any helpful advice?