Period or implantation bleeding?

I have read that implantation bleeding can be heavy. I'm 7 weeks now, and my last 'period' was only 1 day and very heavy. We were also trying to conceive. When I told my doctor this, (after we found out I was pregnant) she said that it could have been implantation bleeding, but because I haven't had a scan yet (not till 12 weeks) she can't be sure, so we'll wait and see. With my first child, I didn't know I was pregnant because the implantation bleeding was just like a period, but not as heavy, but it lasted a few days, so I didn't think anything of it. I hope ye are preggers!!! good luck x