Been having contractions all day I'm hurting so much I can't even sit I'm just now starting to time…

Been having contractions all day I'm hurting so much I can't even sit I'm just now starting to time them but how do I know if they r normal ones I never timed them with my girls I'm 35wks and 3days but he is measuring 2wks and 4days ahead so does that make me 37wks? This Friday they will she how much he is weighing and I will do that strep b test thing anyone had this problem or something at 35wks