Stunned....and a little confused.

Chelsea

So my SO and I are not trying to conceive, but aren't taking any precautions either. So I tend to test around AF time just in case. My last AF was 8/6 and I tested negative before it so I know I wasn't pregnant. We have only done it once this month on the 28th because SO has been out of town. On 9/4 I was feeling way sick and cramping with a small amount of spotting. so I figured AF was on her way and decided to test for the heck of it and got this...

Now as far as I can tell I was only 7 DPO at most! I have never had a test so dark and i tested after a missed period with my last two. So on 9/6 I head to the doctor because I'm still cramping and had spotting again on 9/5. Doctor says that it is probably implantation, but they will take blood and go from there. Results come back at 372! At 11 DPO! Symptoms with this pregnancy have been way bad too. I have two other kids and had NO symptoms. Has anyone else had this and what happened?