Even with a high BMI or other vulnerabilities, your chances of dying are exceedingly low. A nasty case of Covid is comparable to a nasty case of flu - in other words, the symptoms you have are totally normal, and really now anything to worry about. Some potential towards pneumonia is also very common, and you have done exactly the right thing in taking the antibiotics your doctor has prescribed.
You need to rest, make sure that you get plenty of fluids, and try to get some food if you can. Small light meals such as some soup, milk, fruit some toast - you need food to maintain your strength.
And all that is perfectly normal for any viral attack.
If you are struggling to breathe - gasping for breath - then that is serious. If you ever feel that you are heading towards that, or you are worried about worsening symptoms, then you can speak to your GP or out of hours service. If you must phone emergency services then do it - but despite how the news makes it feel, very few people need emergency services or hospitalisation.
I had it pretty much for two weeks. There were two waves to it - I felt ill for a few days then it wiped me out for about three or four days, then I felt a bit better for a couple of days, but then I was wiped out for about three more, then about a week of feeling exhausted. By comparison, I have had flu, and it was no worse (but not any better either). I'm a lot older than you and also have a higher BMI.
Try not to worry. You really do have very, very little chance of dying. Just rest.