6 days after ovulation, i saw little stain of blood on my pant. occasionally i've been weak, little dizzy, wet, headache, stomach pain & now my period?

Pregnancy?: When a fertilized egg "attaches" , a small amount of blood may stain clothes, so when actual vaginal bleeding occurs, (your "period") it is not always a true "period": occasionally a pregnancy may attach to the inside of a "tube" and this will cause symptoms such as your describe, and also cause vaginal bleeding in most cases. Get asap a serum HCG test to make certain.

Pregnancy test: Conception, as defined by the generation of a fertilized ovum, occurs within day or so of the sex. However, it takes about 3 weeks for the embryo to make enough HCG to produce a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.