Help!

So I want to start off by saying that I recently found out that I have PCOS and im currently trying to conceive #2. I already have one and she is 9. So back to the problem at hand. Since starting Metformin a few months back my menstrual cycles have evened out and became regular I have one every month on the day it is suppose to start I have yet to be late since starting Metformin. Last month my period started just as it was suppose to and I BD at least every other day after I went off. On June 11th I had what I assumed to be implantation bleeding, really light pink and only when I wiped, this lasted maybe an hour or two and it was gone and I haven't seen it since. So I figured I would wait until my missed period before testing. Well on the 16th of June I was suppose to start, but no period so I tested it came back negative so I figured I would give it some more time for my period to start because maybe it was off a couple of days. I tested again Friday and again negative. Tomorrow I will be a week late with no period in sight. Is it possible I'm pregnant if I still got a negative test 3-4 days after missed period. Thanks for any insight and similar stories or situations would be helpful and sorry for the long post lol.