First of all, you say that the antibiotics helped? Then what you have is not a common cold. You probably have some sorta flu bug.
Secondly, you are probably more in-tune with your body right now because of stopping smoking and your other lifestyle changes. You were already looking for changes in your body because of that. So now you are noticing every little thing.
Thirdly, when you were sick in the past, you probably used weed to help you feel better. This time you are not, so maybe you feel worse than usual.
As long as you don't have a fever, you'll be just fine.
Oh, and, don't overdo it until your better...that includes working out
