I feel like I have nothing to live for?

For the last few years, I have had a recurring feeling of emptiness inside, and it only really started getting bad in the last few months. I used to have severe anxiety issues, and it still affects me now and then. I feel constantly insecure and self conscious, and I find myself working myself into a bad mood over the smallest of issues, and I would be fine, almost happy with who I am one minute, and then I would be flung into a mindset of self doubt and insecurity. I'm fifteen now, and my summer vacation has just begun, but I don't feel any of the initial relief and happiness that I used to, as I am running into a big exam year next year and I am starting to worry. I always seem to have a pretty pessimistic mind frame, I'm unpopular at school and things are often a little edgy with those who call themselves my friends. I want to meet new people, and make new friends, but I can't seem to overcome my low esteem enough, people usually get the impression I'm weird because I don't speak much around those I don't know. I feel like I can't enjoy anything any more, not even music, which was the only thing keeping me here when things were particularly bad. I sometimes find myself thinking suicidal thoughts. It just seems so much easier than having to go through the next few years like this. I have nothing to look forward to or live for. I have no faith and I'm feeling pretty reckless, like nothing even matters anymore so I might as well do it anyway. I don't know what is wrong with me, could anyone help me, in maybe helping me dealing with this, or simply how to enjoy my summer while I can? Thank you.