How about giving the midwives a call and explaining to them what's going on - they might want to see you before tomorrow's appt? They may not, but it might put your mind at ease. AFM, that's just what all my contractions felt like, strong period pain, I didn't realise that's how they'd feel to me and I'd been having 'period pain' for about 5 days before giving birth. If in doubt it's much safer to ring and check....good luck! Sounds like your body may be starting to fire up