Huge medical question! Help?

Im currentky trying to conveive and Im not due for my monthly until Friday. Yesterday morning I got sick but i felt fine after with slight stomach pains.  Almost like someone was choosing organs at random and squeezing them or shanking me right over where my belly button is.  It wasnt bad.  Came and went until about 4. Then I started getting almost like hot flashes and became extrememly nauseous with the stomach pain becoming more frequent.  After a few hours my period started and I began to feel a lot better. Its also a dark brown/red.  Very light but definately there.  Any insight would be helpful... :(