Miscarriage

So, I'm pretty sure I'm having a miscarriage. Took a test a week ago that I thought I saw a faint line on but wasn't sure so I decided to wait & test again. I have the IUD so I don't have periods & couldn't just count on it starting. Well, out of nowhere I started getting horrible cramps and bleeding. I decided to take a test and there was a line but it was faint enough to still be lightly questionable.

I'm not freaking out over the miscarriage. But I'm trying to figure out if I should tell the dad or not. He's someone I've known for years & we were hooking up for a while. Kinda a friends with benefits thing. We haven't really talked lately because he got a new girl out of nowhere and cut me off. Do I tell him or just leave it alone?

Editing to add a picture of the second test. I had to play with the lighting to see if I was really seeing a line.

Edit again:

I have an appt with my doctor tomorrow.

I was just trying to get opinions on telling him or not.