Confused

I had a d and c on the 11th of June we waited a week and we did the deed and then again a few days later. After the second time I had some pain like my period was coming but it didn't I have been getting some brown stuff when I wipe. I didn't think anything about it because I thought I was the after effect of the d and c. I have done what my doctor told me to do and that was to take a test a couple of weeks later to see if it was a bfn. As I was shopping before I picked up a cheap test on asda and dos it when I came home and bearing in mind I have had a lot to drink today the test came up with a faint bit visable bfp. I dont want to get my hopes up but is there a chance I have been caught so soon xxxx