Don't know what to do..

I'm almost 28 weeks and for the past couple of weeks I've had cramping.. Today I started having sharp period like cramps and my lower back is hurting pretty bad.. The cramps are on and off they're not constant but the back pain is persistent. I'm a FTM and I haven't felt my baby kick near as much as I usually do. Should I be worried labor is nearing? I don't exactly know what to expect but I'm a worried soon to be mother. TIA