My Heart Is Skipping A Beat

I know this is probably going to sound like nothing, but uou know the feeling when your heart 'skips a beat'? Well, for the last couple of weeks I've been getting that feeling in my chest at least once a day, like my heart is skipping a beat. There's no situation causing it and I don't feel nervous or anything. I don't like to trouble doctors, especially over small things. Do you think this could be something? Or just nothing? By the way I'm only 23... I don't drink coffee, barely have tea and don't drink fizzy drinks - I mainly just drink water. I've been very tired lately but it may be because I'm due on in a week. I admit I don't exercise as much as I should but I'm still within my BMI healthy range. I don't eat excessive amounts of chocolate or sweet things either - I went on a diet recently and ever since my cravings for a lot of things have diminished! lol It's true I'm about to start my last year at university and I have a LOT of work to do as well as applying for masters and funding (I'm wanting to do it abroad - don't make it easy for myself eh?? lol :-P) I've been sitting at the computer now for an hour an a half and I've had the feeling at least 5 or 6 times now just sitting here. Also have diabetes running in one side of my family and heart problems in the other.