Cramps

I haven't seen my doctor yet but we're thinking I'm around 5 weeks. I've been experience quite a bit of cramping, some heavy and some light. Sometimes it just happens and sometimes it happens after walking. My husband took me to the pier since we live so close, after walking to the end and back it hurt my uterus so bad to walk. I've miscarried twice and I'm a little concerned. Is this normal?