Spotting between periods

For the past 6 months or so, I have had a couple days of spotting between periods, usually a week or less before my period is set to start. I am on a birth control pill that I have been on for the past year, but I have taken other types of pills for the past 4 years (had to keep switching for other medical issues). For the first 6 months of the specific pill, I had no spotting and no issues. There is also a correlation that 6 months ago, I started really watching what I ate and exercising and I have lost a little over 30 pounds since starting. I'm now at about 156 pounds, 5 foot 1 inch tall, age 23. I am about half way with my weight loss. I just didn't know if other people had experience with increases spotting between periods after starting their weight loss journey? I know it could potentially be something else, but I thought I would ask first before sounding the alarm and seeing the doctor.