Pregnancy complications. On with me!

Sir im from pakistan. I have a positive pregnancy test after 5 days of missed period but one day later i feel one spot just like finger nail i go to gynecologest he suggest me progestron injection even then using progestron every morning i see a spot like finger nail. But after 10 days spoting stop and then after 15 to 17 days from missed period my preg test turn to negative then i go to docter she perform u.s once again she tell me gastinal sac has seen but im too confused if pregnancy showes on u.s then why urine test showes negative. After all she prescribe abortion tab Misoprostol to abort it.. but i did not take becoz i have some doubt i have no pain no bleeding also have some preg symptom.. but confused what i do kindly help me whats going on with me thanks