There are several pinned posts here in the college life forum that will address many of your concerns, so look at those first.
Your college will have a medical office. That should be your first stop if you get sick. Many kids don’t take care of themselves as freshmen. Mono is common. Get enough sleep. That’s crucial. Don’t just eat junk, avoid drinking too much alcohol. Bring some basic medicines with you: pain killers, cold medicine, antihistamines if you have allergies, eye drops, antibiotic ointment and bandaids, etc…
No one is going to think you’re weird if you have a single. Why would they? Lots of kids have singles. Be glad you might not have to share your personal space with someone.
Don’t find things to worry about before you even get to college. Relax. By far, th vast majority of students get through their college years successfully, and you will too.