It's positive!

Back story: I was diagnosed with Thyroid Disease when I was 12. I have 3 healthy kids, but before I got pregnant with my youngest (he's 1) I had 2 miscarriages in 2016. I also had another miscarriage July 2017. I was pregnant with twins and lost them both at 7 weeks. That pregnancy was a complete surprise, but after the loss of them we decided to try again. AF was due today, but I've been testing all week only to get BFN. I had one test left and just decided to use it to get rid of it. To my surprise it came out as a faint positive. I went to buy more tests and they also came out positive. I don't want to tell my husband until I've had my first ultrasound, and I'm a little concerned because my positive showed up so late in my cycle. With my other pregnancies, even the miscarriages I found out at least a week before AF was due. I guess I just need some reassurance that this is normal? Also, am I wrong for not wanting to tell my husband right away? I just want to be sure everything is okay before I tell him. I don't want to see him hurt again. TIA everyone!