When to go in to L&D?

Last night I was having some mild to moderate contractions about every 12 minutes pretty consistently. Today I feel like I'm giving birth to razor blades. Sharp pressure and slicing pain in my cervical area. I've been too busy dealing with my 4 year old this morning to try to time contractions. Do I just sit it out at home until I'm bleeding/my water breaks and/or I'm having a hard time talking though my contractions? Or do I go in early because I'm only 34 weeks?