1st & 2nd day of period normal flow (bright red w/ clots) morning of 3rd gone & came back in afternoon. 3rd,4th,5th day light flow. pregnant or not?

Depends: Many factors can throw off your period. This could be a normal period. However, early pregnancy can be associated with bleeding. If you are sexually active then check a pregnancy test and follow up with ob/gyn. If bleedng is associated with any othe symptoms such as fever, lightheadedness, dizziness, shortness of breath, nausea, vomiting then follow up ASAP. Otherwise wait and see