Um, you sound pretty normal to me... why don't you use condoms? When it comes to stuff like that you can't really play it too safe. I'm not exactly sure what you mean when you say "off my food." Many things can make you tired and they range from not getting enough sleep (duh) to not eating enough.
Well, how is your diet? Are you eating the proper foods? Are you getting plenty of rest? Are you getting some exercise (I know, difficult when you are tired, but some physical exertion might be what you need to get some good sleep)? Are you at a good weight? Are you under stress?
If sleep, diet and exercise do not help (or if you can't seem to get your stress under control), try to see a doctor. There are various physical ailments that can casue this that, with treatment, will help you feel much better.