Flight Planning looks hard to anyone at first glance but once you go through the subject you realise it's just a matter of practicing with charts and question bank. Met requires much more brain work and time to master and understand it. So with that time gap, there's high chance you will be running out of time and of course rush to get at the end of it which trust me it is the last thing to do with a subject as MET if you want a first time pass and a good score. In my humble opinion, you should consider to attend RADNAV and FP at your next exam sitting and drop MET at the moment.