First, I haven't any idea what your trouble is and I think it will need a doctor to tell you that so you should see one or visit the clinic as quickly as you can.
The chances are it is an easily treated infection. To the best of my knowledge the serious ones don't show symptoms for much longer than 24 hours.
In future you should be more careful with your choice of friends and what you do with them.
Just because you are paranoid it doesn't mean they aren't out to get you (almost a proverb)!