Is it possible to be immune to coronavirus?

So basically my entire university flat has been showing corona symptoms and two got tested and came back positive , scary right?


Well 10 days later and everyone has pretty severe symptoms (coughing fits,rashes,high temperatures etc)

Except me , I have been 100% fine . I can still run 7 Miles (by doing laps of hall until I get to 7 miles as we cannot leave our flat) and I still have perfect mental health with not a single headache


Now, I still hang with all 5 of these covid positive people , we watch football in the flat lounge together . We basically thought that we all have covid so what's the point of social distancing when everyone except me has either tested positive or has the symptoms. we all sit pretty much next to each over and not caring about coughing or anything but yet I still feel fine?

Im not really that fit but I am guessing its due to my immune system as I have not been sick in like 4 years.