Period pain on right side 38 weeks?

I'm 38w2d. I had a bleed and what I think was my 'bloody show' at 36 weeks and I was admitted to hospital just to keep an eye on the bleeding. Ever since then I've had this period type pain that comes and goes, not painful just that dull ache but it's only on one side and seems to be in the groin area. It is getting stronger over the weeks but nothing too painful yet. Does anyone have any idea what it could be? I heard it's normal to get pre labor period pain at this stage but is it normal that it's on one side and in the groin?