Have you applied for credit? Or do you currently have credit cards? Using more than 30% of your total credit (raising your balance) can effect your credit score, or maybe a past due account hit your credit report. But if none of this is true, check your credit report. Your allowed 1 free credit report from all three credit bureaus in a 12 month period. Late fees, closed accounts etc., can effect your credit, or having a joint account with someone else can as well, in both a negative and positive way.
