Good advice from VFE. Most people have pangs of doubt as they approach the exams, often that period between finishing the syllabus and waiting to go on the 2 week crammer just before the exams.
I don't know if you are a distance learner or full time. I've done distance learning, and I can tell you that just before the 2 week crammer course, I passed all my progress tests, but when I looked at sample exam questions and papers, I couldn't answer the majority of the complex questions - Nav left me feeling pretty cold, so did Met. It's important that you understand the key concepts of the tough subjects: Nav, Instruments Met etc, but it is unlikely that you would be able to pass an exam before the two week sessions.
You are about to go into feeling miserable mode, but I wouldn't worry about it. Work hard on your crammer, and then you should be ok. (Be warned that while on the crammer you will still feel like failing all the difficult subjects...)