Positive Test After Abortion

Hello
I really hope you can help I am worried sick. My normal monthly cycle is 31/32 days. My LMP was 4th June I had a termination on Tue 14th July (surgical). I then had the depo injection on Tue 21st July. I then had sex wth my partner on Sunday 26th July. I was told to do a pregnancy test 3 weeks after my termination. I have done 3 over 24 hours and all come up positive but extremely faint and it does take quite a few good minutes for it to show. I am worried sick. Could I be pregnant again? Or are there HCGs still floating round my body?