Hi there - honestly that does sound a little bit fast for all of that to be happening - while it's completely possible you might be pregnant, if you're worried about the fact that you might be pregnant, these stresses, fears and worries can easily cause nausea, stomach cramps, headaches, etc. Just think about how you felt right before a super important hard test - nervous and worried.
Obviously you should take a pregnancy test - are you late yet?
But these symptoms might be related to worrying about being pregnant - if any situation was going to cause extreme tension and stress, the fear of being pregnant certainly would.
Let us know how it goes - most important thing I hope everything turns out the way you want it to :)