I'ts normal. 

You shouldn't stress yourself out. Babies are still quite small at this point. Doctors don't become concerned about feeling movement till 20/22 weeks, which you're in the middle of. And they don't worry about continuous, countable movement till 28 weeks. It's normally not to feel your baby move every day because again, they are quite small. You could be moving and miss their movement.I'm 37 weeks and it's still hard for me to feel my little alien move if I'm standing or moving; I can feel it but it's not as strong as when I am sitting or laying. So if you're quite active, that can be it right there.And from what I understand, the nurse sounds as if she's concerned about the bleeding because of hemorrhoids or you're straining yourself too much while going to the bathroom. I could be wrong, but that's what it sounds like.Try drinking something cold and laying on your right side for a half hour. It usually gets them moving.   

Doctors don't have you keep track of baby's movements til after 28 weeks because up until then they can be so sporadic. I know it's hard not to worry but keep that in mind. Hope you'll be feeling lots of baby kicks soon!