What is wrong with me?!

La

I just had a sudden headache come on and go away all within about a minute and a half... I felt very fatigued and "dizzy" for about 3 minutes and I had the sudden urge to have a bowel movement. What in the world?! Im day 26 on my cycle. Any ideas and what could be happening? My husband and i did have unprotected sex about 10-13 days ago. Has this ever happened to anyone else before? Implantation maybe?