I've never been diagnosed with one myself, but I've done my fair share of waiting for results and being around people who have had a diagnosis. I think, like coping with most things in this world, the only way to get through it is to live in the moment. Obviously thoughts about the future will creep in and sometimes there are decisions to be made, but while you are here you have life. That quality of life might be impaired by illness, but people do manage to still enjoy and cherish life while they have it even in what might seem like desperate circumstances.
I'm probably being hypocritical saying all this, because I've been a worrier forever and I'm all for indulging in some doomy and gloomy feelings more than I should, but I am starting to learn that the only thing you can do is make the most of what you have now because the future isn't guaranteed for anyone. I would say don't make any rash decisions re. college but once you have a diagnosis think about what
you want and try not to think what others might advise you to do or what you
should do. The only right way to cope is to do things your way. If you feel able to continue with college and you enjoy it there's no reason why you should leave. Even if you might struggle to attend ask for help and I'm sure you'll be given it. On the other hand if you feel like it's a waste of time and you don't really enjoy being there and doing what you're doing then leave and spend your time doing something that feels worthwhile and makes you happy.
I'm going offline now for the night but if you need anyone to talk to my PMs are always open and even though I'm cutting back on TSR use these days I do still check my PMs and would be happy to chat to you or just listen if you feel the need to get things off your chest.