Pregnant?

I had a miscarriage in August, had my first period afterwards in September, and have had one every month since around the same time.

My last period was November 26th - December 2nd.

When I took my ovulation test Tuesday morning (5th) it came back positive. I was shocked because I didn't think you could ovulate so quickly and glows prediction was to ovulate on the 14th!

For the heck of it, not sure why, I felt like taking a pregnancy test. Well, it came back positive. I was even more shocked. I had JUST had my period, how the hell am I already pregnant and getting a positive. Well to be sure, I've taken one every morning since. They've all come back positive and had clear dark lines. According to the pregnancy tracking app I'm 1 week pregnant.

I'm very confused to say the least.

But to add into it, I have had mild cramping in my lower stomach/abdomen since last night. Nothing painful, just annoying and uncomfortable. Also, a bit tender when my DH and I had sex last night. Again, not painful per say, but very uncomfortable. I woke up this morning to take my test and when I wiped there was a little blood.

Could it just be implantation? Or could it be the pregnancy not sticking? I'm not sure if I should even call my OB yet because I'm not very far along at all. During the last pregnancy they wouldn't even see me until 8 weeks and that's when I miscarried.

Sorry for the length, and if I sound uneducated. Thanks ladies.

Also it may be worth mentioning that DH and I have done the do the past 4 nights despite being tender every time, and this is the first time I woke up bleeding. So I don't think it's because of that.