Feeling light headed and dizzy

Natallia • 24 yrs married 14/1/17, been waiting 2 years and finally have our little boy 💙🥰

I’m 39+2 and I’ve been feeling light headed for about an hour/hour and half now... when should I ring someone? I’ve sat down had a cuppa and had some food to try and help but it hasn’t helped! Should I be ringing someone? I had a sweep done today dunno if that might have something to do with it 🤷🏻‍♀️