spotting and cramping in 3rd trimester

i am currently 28 weeks and 4 days pregnant and the last couple of day my stomach has been cramping i thought it could possible be constipation, i have been poopong but only small amouts and was stuggling to do that. but yesterday and today i noticed some light pink spotting just enough to make a streak on the toilet paper as i wipe (i havent had sex recently) i called my doctor she didnt seem to worried about it and i have a doctors appointment on wensday june 6 (in two day) do you think i should be concerned?, do you think this is normal?, shouod i go to the doctors now or just wait till my appoitment on wensday? this us my first pregnancy and im only 19