I need insight

Samantha
The week before last was my break week and I had my period. I had sex two times since (the day after my period and 4 days after) and I had some blood. Then I had pain that made me feel like I couldn't eat and I was full always, went to the doctor and he said gastritis. That was 3 days ago and he prescribed me Zantac. Thiguht it was working but today I woke up and my back hurt all the way around to my stomach and it was bothersome to stand, but went away if I layed down. And when I peed this morning it hurt and when I wiped there was light pinkish blood. I am a perfect pill user. The doctor ran a urine test when he diagnosed me with gastritis, and a blood test because I am anemic, what's going on? Would that show if I was pregnant? Or not possible?