Lowering credit limits

Over the last few months, everyone of my credit card companies have lowered my credit limit. I had a 740 credit score and over the last six months it has dropped to 575. I had not had any late payments at all, i use all of my cards...none had high balance...but do carry balances. Now, everytime I use a card, i get letter saying they lowered my credit limit and i am maxed out. Im talking six or more credit cards....it is killing me. I leased our cars and i have to turn them in in january. I will not be able to get another lease or buy a car with that credit score. I dont know what to do. I have no late payments, no collections, i have a great job, own my home....and i have a credit score of 575??? Any suggestions?