Trying To Conceive

I am not sure if this is in the right section of the forum. Please correct me if I am wrong. :) 

Well,

I have had unprotected sex on the 10th, 11th 13th of June with my boyfriend and uses the pull-out-method but him saying that he might have impregnated me, all I can say it was unplanned but we've said we always wanted children. So from here I was trying to conceive.

On the 15 & 16th of June I had brown discharge (almost old-period like) and some very light pink spotting when wiped but not heavy enough to need a pad (maybe implantation bleeding?) and I would only see it or get it when I am going to the bathroom and wiping after I am finished. I know it takes about 6 to 10 days for implantation to occur and sometimes even less depending on the woman.

Then I have gotten my period as expected on the 17th of June with heavy bleeding and thick clots and lasted a number of appropriate days that I am used to. And I have had my period as expected on July 15th with also a number of appropriate days that I am used to (I have reading on vaginal bleeding and period bleeding, but I couldn't tell the difference so I am not sure). 

Now it is August the 9th and I have been experience sever lower abdominal pain and shoulder pain all on my right side of my body that seems to come and go for the past five days, I have heard that this could mean a miscarriage. I am expected to have my "period" on the 12th of August.