Twinges!? 13 weeks pregnant!?

Hi all. I'm 13w 4d pregnant and I'm getting these weird twinges, they don't hurt but I'm just wondering what they are. They feel as though they are inside like my cervix is twinging :s I don't know if the twinges are there but it feels like it is. Iv been gettin it since about 8 weeks pregnant. Iv had my scan and baby is fine im just a worrier lol This being my 1st pregnancy I'm scared, I dont know what to expect or what is normal or not. Are these twinges normal and has anyone else experienced these? Thanks :)