My periods date is 15th August, I have 28 days of regular cycle, last periods start date was 18th July. I had unprotected encounter on 25th July (pull out method). Last night I noticed some vaginal bleeding, which was unlike my normal periods. The blood (4-5 drops, red in color) was all over the tissue when I wiped my vagina. Ever since I had unprotected encounter I have been feeling this vaginal sensation like the urge-to-pee everytime. Yesterday I couldn't pee for several hours and hold it off due to travel, and my bladder was so full, that when I finally peed there was this too much pain (sensation-like) in my vagina. Could this blood be because of that (sudden pressure in bladder) or is it implantation blood? Please suggest if it's pregnancy symptom or something else? It was just one time blood spots, didn't observe it subsequently.