I have a regular 30 days cycle period.my last period is last Jun 3, i took Gonal-F injection for fertilization?

I have a regular 30 days cycle period.my last period is last Jun 3, i took Gonal-F injection for fertilization, between Jun 4-15, we got intercourse Jun 15-19 straight once daily, then i got a very light spotting last Jun 22 & 23, and a bleeding Jun 24- 27, its medium heavy but not that heavy, unlike period and I don’t feel lower abdomen aching unlike menstruation, and this is not normal to me…And I feel backaches since I got that spotting until now even I don’t have the bleeding anymore.Is it a menstruation? Or implantation bleeding? Is it possible that i am pregnant? We are more than 2 yrs married, and we really want a baby now. pls help.