I'm sure it's from straining. It's scary, for sure, but hemorrhoids will bleed and it's not really the same thing as "blood in the stool".
This happens, not only just to women. My brother in law actually had to have surgery to help him out. It is such a personal subject, he wouldn't talk to anyone about it and wouldn't go to the doctor either. He felt so much better after he had them fixed he said he wished he hadn't waited so long.
So, in your case, being pregnant, I'm pretty positive it's just from straining, etc. Try taking a stool softener or drinking warm prune juice. It may be a wive's tale, but warm chocolate chip cookies right out of the oven are supposed to help also.
Talk to your doctor about the best ways to manage things through your pregnancy and discuss whether or not you need a little surgery to help after the baby is born.
Don't bite your nails off. Hang in there.
I wish you the best!