I just got hired on to an ambulance and feel that my 2 months I had to spend working through an investigation for my cert (refer to my first post if you are wondering) took some memory from me too, but I have a couple apps on my phone that honestly help me out a lot with practicing information that I learned in my EMT class. If you have a smart phone, check out the screenshot I attached. They are Android apps but if you have iPhone, I know that a few of them are available to you, as well as iPhone only apps that could help. They have free quizzes and references that show medication info, illnesses, etc..
Another source is
https://www.fisdap.net. (but you do have to pay for this one). My class was given a key for access to this site that we paid for in our materials fee, I think it was, alone, about $30 or something. It contains information for review and also is the most closely relatable source for practice and word familiarization to the NREMT exam. It is one of the biggest helpers if you ever need to retake or have a friend who needs to take the nremt test because the wording is very similar, in my opinion.
If you're looking for free, though, definitely check out the apps. They are awesome!
Last suggestion is to Google anything you have a question about and add 'emt' to the end, it usually takes you to an EMT forum where paramedics or other EMTs share there knowledge to others who wondering about the items in question (i.e., contraindications of nitroglycerin, CPR questione, etc.)....orrr refer to the book and look up whatever you feel unfamiliar with. Good luck!