Throwing up blood while pregnant?

Did/does anyone else who is pregnant have problems with throwing up blood? It's not a every day thing. But often. When I mentioned it to my doctor a few months ago she had mentioned it can happen. From throwing up too much/ being anemic. I never really took test to say I was anemic. But took her word for it that it was normal or more so a side effect some pregnant women get. But sometimes it worries me. I throw up stomach acid often. & it's accompanied by abit of blood. Not an alarming amount. But enough to where I'm wondering if anyone else has dealt with it because I've never heard of it before. I also throw up abit blood when I throw up too. I don't throw up as often as I did the first/second trimester. But it's still annoying. I'm 22, & a first time mom. I don't have any type of allergy, or some type condition to where it would be considered "not surprising." ...Tums does help a lot with my acid reflux & whatnot. ..I'd just like to know if any other mom to be or moms had this problem while pregnant. I'm 28 weeks & 5 days. It's unfortunate that this is one of those things that happens to some while pregnant. :/