Hi I Usually Have A Standard Cycle Of Heavy Flow

Hi I usually have a standard cycle of heavy flow to normal flow with painful cramps during the beginning of my cycle. This month I've had minimal cramps and a much lighter flow to something I would consider as spotting. I am not sexually active(I'm a lesbian) and I don't exercise, but I have been under stress this month due to my job. I drink frequently and smoke cigarettes. I started taking Motrin when I thought I was getting my period as a preemptive strike for the cramps. But I was spotting for a day or two before what I thought would be when I would start my period only to have a very light flow the day after.