Hello. I got my menstrual cycle normal a long time ago. 4-5days normal bleeding. Every 30-35days.

But now, I am experiencing 1day period last month and then now. I am not an athlete or do heavy exercise. My period only lasts for 24hrs or even half a day only and it is so little that I don't need to use pads. What's the meaning of this? I am only 20years old. Please help me, it is possible for me to get pregnant? But I think that's impossible because I am sexually active a long ago and never get pregnant.