You need time out to get your mental health in the right place before you go to Uni.
Honest advice? Cancel your UCAS application for this year.
Your head is all over the place and leaving home / going to Uni is stressful enough.
Once you have your A level results, then make a decision about retaking (your school should be sympathetic to this idea if they are aware of your recent issues). Go and see your GP and get some counselling help.
It will take 1 year+ to get your head in a better place and you can't just rush to Uni and hope it will all be okay.