Hemorrhoids can be awful, whether they are around your rectum (external) or inside your intestine (internal). They can hurt, make having a bowel movement painful, and they sometimes bleed. Hemorrhoids are actually engorged veins, something like varicose veins. Internal hemorrhoids cannot be seen when looking at the rectum but exist just inside the colon. Hemorrhoids are very common in pregnancy and cause pregnant women lots and lots of discomfort. Hemorrhoids often bleed red blood, which can be scary. What you describe about bleeding but no real blood on the toilet paper is common. A real problem with hemorrhoids is too much bleeding, causing anemia. That's not good for a pregnant woman, so you need to take some steps to make sure they don't bleed much.
Here are some helpful hints for dealing with hemorrhoids:
Internal hemorrhoids, which cause a lot of bleeding, do need to be treated, so make sure you discuss this with your doctor.