You DEFINITELY need to stop reading online about symptoms!
Originally Posted by
currygod 
I mean, I've noticed when I exercise it takes ages for my heart rate to become normal again, and I looked online about it and it said it could be an early sign of heart disease!
This is a CLASSIC example. This is also a classic symptom of another condition - lack of fitness! It is NORMAL for unfit people to have their heart pump furiously for many, many minutes after exercise. (This is from memory, but the generals are true). Top competitive runners can get their heartrate up to something like 250 per minute while running, and in something like a minute or two it goes down to their resting rate of 40-50. Unfit people would almost certainly have a heart attack at that rate, and after exercise it can take 15-20 minutes (or even longer I think) for the rate to go down to resting rate.
At the end of the day, SMILING can be the symptom of a serious illness (can't remember the House episode :-)) but there is a much more likely explanation - you are happy
. We have all been trashing our bodies with poison - it's no wonder at all that we don't feel healthy. I'd give it a year of healthy exercise (slow, and preferably planned out with a trainer) before starting to look for symptoms of anything :-).