Questions about period? pls answer?!

Ok my period has changed when I first started I got them it came once a month. Now that I'm 23 and became sexually active my period changed.. It use to come the 5 the of every nmonth now it comes whenever but I never skip a month. I also have pms two week oe more before my period arrives also I have random pelvic pain its mild but noticeable. My period use to start of red and heavy not abnormal heavy about 4 pads a day. Now it start of light and light pink and gradually turn red. Last month it started orange than light pink to red. Also I have cramps just in my pelvic area. sometimes just on one side and it alternate. Has my period become irregular? Do I have a serioud problem? Am I unable to have. Babies? I'm std and sti free!!!