Kudos to you for using protection.
But hun even if you were have early pregnancy symptoms... which I don't really think headaches alone are.. They could be from anything.
The only thing you can do is wait for your period. If your late, take a test.

if your period isnt due until the 24th then you still have 14 days left, you should be ovulating about now if you have a normal 28 day cycle

ovulation can cause headaches, so can stress, and many many other things

if your uing protection and it hasnt failed dont worry too much, if you cant help but worry you may want to think about getting another form of protection, double protection (pill and condom or some combo...2 condoms dont count as double protection it makes it less effective actualy) is very good

if you miss your period though take a test and go from there

~alicia~

You can get pregnant from using a condom, that's how i'm 38 weeks pregnant! Just try to relax, wait for your period chances are it will come