I am new to this site so I want to thank everybody who have a answer and look at this question... Me and my ex-boyfriend was together almost 3 years but we came to an end about 3 days ago and now I think that I am pregnant we had sex about 3 to 4 weeks ago and we didn't use protection and now I'm experencing light bleeding stomach pains headaches and everything above I don't know what to think I am needing help

Could well just be a light period do to the stress of the break up if you are worried go do a test no one here can tell you if you are pregnant sweetheart we can just give you guidance.
Stress can cause all kinds of strainge things to happen to the body from light periods to heavy ones to stress headaches etc.
Good luck xx