I feel like s loser, hopeless a faliure at life?

At least give everything your best and be a good person. That would make you admirable, even if you aren't good at gym or talking to girls. It would also help you to get through your current hardship and prepare you to be a successful adult. Remember the tortoise and the hare: the hare was a better runner than the tortoise, but the tortoise had a better personality, which allowed him to win the race. You might just be developing more slowly than the other students. You'll probably discover your talents later.