I Have Been On Sprintec For Several Years Now And

I have been on sprintec for several years now and just got married a couple months ago. The past week or so, I've had some different symptoms that I'm not used to. I've been very exhausted, dizzy at times, heart burn, constipated, and had a period that was lighter and shorter than normal. I've never missed a pill, so I'm unsure of what this could be. I have taken a pregnancy test a few days ago and it was negative, but I know something is definitely different.