Hi and welcome. This may sound like a cliche but you're only 18. You have your whole life ahead of you lovely. You have plenty of time to achieve something. Have you spoken to your GP about how you're feeling? Have you had counselling/CBT? On medication? Sorry for all the questions, just trying to get a better idea.
Do you have any support at all? It might be worth speaking to student support at your college/uni. Your local mind can also be a good resource.