Normal or contractions ?

Im 31w2d and for like a few weeks i been having period like cramps i start by having pressure/pain on my pelvic area then it goes to my lower back and sometimes tightness/pain by lower belly by my belly button all this lasts for 5 mins or less , its been happening every day and i get this pain for atleast 4 or 5 times a day, but i am not sure if this are contractions, bh or normal? im a ftm and since they happen hours apart i dont think they are contractions but idk..if i were to got to l&d by the time i will be there the pain will be gone and i will have to wait hrs for the pain to come back..i do have an appt. on monday and i will mention it to my ob but for now what fo u guys think?