I had a chemical 12/9

I was supposed to ovulate 12/25 but normally I have a 35 day cycle so it could've been later. I just wasn't fully paying attention. It was my first loss and it really upset me. I have 3 girls and no lolses up until December. 

I checked my clear blue digital ovulation and when I didn't get a smiley so I just stopped test after 12/25

Went to my OB on 1/8 and got a negative Urine pregnancy test. 

Still no period....... finally Saturday the 16th I took a test and got the faintest line EVER. 17th it was darker and digital was positive. I've taken roughly 1 million tests. They all look good. Unlike my chemical. 

Not sure how far along or when I ovulated.... but called my primary on Monday because my OB was closed and they did a blood test and my HCG levels were 63.... no one seems concerned about it. So I went back Wednesday and my levels are 129.... they doubled. So I should be thrilled. But that number sounds so low. My chemical never got above 15 so I have nothing to compare it too. 

I got for one more blood test tomorrow. My strips and first responses are all darker- which is great.... and it's doubling... also great. But is this number too low to be successful? Anyone have any experience with this? Please help!