Step I I seem to be getting worse? Test in 10 days, Freaking out!!

Last week, I took an NBME 7 and got a 219 on it. My goal is at least a 225. I was satisfied with that. At that point of time I was getting at least 65% on the 46 block timed uworld questions that I was doing. Sometimes I scored in the 70s. For some reason, the more I study, I've started to deteriorate to about 60-63. this is freaking out mostly because the uworld averages are starting to increase and I was always at least 5% above them. Now I'm only 2-3 points above and sometimes even below. I seem to be have problems in general, and don't have a particular subject that I need to brush up on. I mess up in a different subject everytime. my test is in 10 days and there's no choice of postponing. My school won't allow it for some reason. I was going to take an nbme tomorrow. WHich one should I take 11 or 12? WHy am I getting worse? What do I do?? PLEASE HELP!!!