5 weeks pregnant and cramping but no blood? I'm worried

Stay calm. Not unusual. Hydrate, rest, Tylenol (acetaminophen) if necessary. If persists, severe, or other symptoms, let your health care provider know.
Cramping. Some cramping is common around 5-6 weeks and even light spotting can happen. Avoid sex for now as you will cramp for 2-3 days afterwards. If the cramping is one sided that is a bit more concerning for a risk of tubal pregnancy or ruptured corpus luteum. If tylenol (acetaminophen) relieves the cramps, its likely just your uterus growing or cramps from sex.