what's happening?

Last month, when I had my "period" is was very light and kept going on and off. Some days didn't even come and only bad light pink when I wiped. It came a day later than usual last month and ended very soon. It was for like 3 days. This month my period came a day late again. It was definitely a period by the looks of it but only last for 3 days. Now it completely stopped and sometimes have light pink when I wipe but rarely. I have been on the pill for many years and never had irregularity. Could I be pregnant? Has anyone had this and what did they figure out? Took these tests.