REALLY anxious.... I just need a few awnsers

so im a bit anxious about my period cycle ...(Im 17, 5'7, 138lbs).. ive been noticing that my period used to last 7-8 days and through all days ive bleed tremendously, too much. Now its lasting 2-3 days with severe cramps before and after (very unbearable). Id go to a doctor and check things out but Im honestly a nervous wreck when it comes to Drs...I dont trust them.. soo I wanted to ask you guys if thats normal? has this happened to ya'll? A drastic change length of time?