Hi I Am Taking Rivaroxaban To Treat A Pulmonary Embolism.

Hi I am taking rivaroxaban to treat a pulmonary embolism. I have been taking them for around two months lately I am getting headaches,feeling really dizzy to the point I almost pass out on occasions keep getting a pain in my left side also.I have visited the Dr on a few occasions for him to tell me each time I'm fine so I haven't bothered going back.any idea what the problem could be?