Unprotected Sex, Pink Vaginal Discharge When Wiped, Blood Flow While Urinating. UTI Suspected. Suggestions?

Hi I'm 18 years old , i been having unprotected sex for the last two months since march 5 , 2013. March 26, 2013 - March 29, 2013 was my last period. My period was due either on the 19 or 20 of April 2013, but never came on. On April 23, 2013 i began to notice a light pink blood when i wipe , April 24 the blood became darker but only flows when i pee, as well on the 25 of April so the blood wasnt flowing out on the pad, the most amount i gotten on the pad was the size of a quater, my main question is how is it that one day i spotted then the next two days i flow blood when i pee now today April 26 i only see it when i wipe. I ate two toaster egg and cheese scrambles and after that i ate just the icing to the toaster strudel and after eating the icing i now feel a little sick like throwing up ? What could this be ? I went to the doctor they told me i had a UTI could that be the reason , or could it be implantation bleeding,or change in my cycle ?