It's very common around that time. As it was explained to me, when the placenta takes over your hormone production, there's a weird shift in your hormone levels, which is normal, but can cause some bleeding. The placenta usually takes over around 10-12 weeks. With my first pregnancy, I was 10 weeks and in the shower and looked down and there was literally blood running down my legs. Like it was a lot of blood. Really frightening. It carried on red for about 20 minutes and then just brown for the rest of the day when I wiped and then spotting on and off for a couple days. I had an emergency scan at the EPU and all was fine. No more bleeding the rest of my pregnancy and my daughter is 4 now. It's really so common, but that doesn't mean it's not terrifying. If you otherwise feel fine, that's a good sign. Did you recently have your scan or do you have one coming up? That should hopefully provide some reassurance. Even given my experience, if it happened to me again this pregnancy, I'd still freak out. That's totally natural. I think everyone would. The good thing is that most of the time it's nothing to be concerned about.
Also, just because you see blood doesn't mean it came from your uterus. A few weeks ago, I had some itching and irritation and thought maybe I might have thrush or BV so I got one of those thrush test kits you can buy OTC. I did it, making sure not even to stick it in very far, so it didn't even get close to my cervix, just inside the vagina to collect some discharge. But in the process, I stabbed myself sort of hard on the labia on the way in. It didn't even really register at the time, but afterwards, I wiped and there was blood on the tissue, not much (nothing like with my first pregnancy), just a smear of red-brown blood. Of course, I panicked. But after a few more wipes, it was obvious it was coming from one spot and I got out my mirror and looked and I'd literally just scratched the skin on the outside and make myself bleed. Such a silly thing and I panicked, but obviously it was nothing. It stopped in like 5 minutes.