Can There Be Blood Clots With Implantation Bleeding?

Personally with my Daughter I had implantation bleeding. Which continued for 4-5 weeks. Due too at my early scan there was a small blood clot just above where my baby implanted. Which then I had small clots pass around when I was 7 - 8 weeks pregnant. She is now a healthy 9 month old.

When I was pregnant with my first child I had implantation bleeding about 10 days after conception.  It lasted for 2-3 days and was light pink / brownish.  I had a few small stringy, dark red spots too which was scary.  I thought they may have been tiny clots.  Thankfully all was well.  This time around, I am almost 7 weeks pregnant and am experiencing some bleeding which my doctor thinks may be implantation bleeding or post intercourse bleeding.  I have had it since May 11th (I was 6 weeks and 2 days) and it is lighter than my period.  I had an internal ultrasound done and they saw the baby's heartbeat which I was thrilled about.  On May 14th I had blood drawn to monitor my hCG levels and am waiting to hear back.  I am anxious to find out what is happening because this spotting is scary.  It has lasted for 5 days and has been accompanied by light back pain (just today).  All other early pregnancy symptoms are still here but I cannot wait for this spotting to stop.  If something like this has happened to you then please share your story.  Thank you.