How To Treat Menstrual Irregularity?

Hi, I am 29 and have had the funniest period ever, i have a cycle that ranges from 29-35 days. But this time my period was early 3-9 days depending on which cycle i go for, 29, 33 or 35. 33 and 35 are the most common i have had the last 6 months? the period was extremely light lasted 3 days had 3 bouts of brown blood, I am also experiencing cramps lower left abdomen, am bloated, my arms are discolouring. did a preg test it was negative? what can be up?