Can On And Off Constipation, Pains In Upper Left Abdomen Be Signs Of IBS ?

Female 28....Been suffering from constipation on and off almost my whole life. Battles with constipation became worse after having my son 9 years ago. Last October I suffered nausea a week at a time for 5 months. Had ultrasound to check gallbladder, no stones. Gyno put me on bc because my symptoms usually would start a week before my period. Nausea stopped but for the past couple months I ve been having pains in my upper left abdomen near my rib cage. I take nexium and probiotic daily to try and ease symptoms but still occasionally have to take a exlax to ease constipation. And just today I ate a bowel of spinach and give hours later notice undigested spinach in my stool. Can these all be signs of ibs? My mother suffers from this as well but hers is more diarrhea than constipation. Also my grandmother was diagnosed with colon cancer at 56 and I m completely paranoid!!