Constant Cramping

I am 34 weeks 3 days and lately I've been having constant cramping that goes to my lower back and sometimes my inner thighs. My first pregnancy, which was 15 years ago I had pre-eclampsia and by this time I already had my son. These cramps come on about every hour or so and I've been having them for a week or so already. We are in the triple digits here in Cali and maybe the weather is making me cramp up. My feet are also so swollen. At my appt last week, Dr said this can be normal buy he'll be monitoring me weekly. I feel like my body will not make it to 40 weeks.