What Causes Spotting Instead Of Periods With Tiredness And Bloating?

Hi My name is Lisamarie. I have a question i have been getting my periods regular for the last 2 yrs since i lost weight. the last 2 months i spotted around the time of my expected period and the last 2 weeks i have been spotting pinkish very diluted on and off.. Sometimes even after sex or an orgasm and then it dissapears. I am very tired and very bloated gassy what can be going on???