How do I keep track of where all my inventory is?

Putting things away is the easy part. Keeping a clear picture in your head of what is where, across everything, is what overwhelms you, and no wonder. Nobody can hold all of that in their mind at once. The people who seem to are not remembering it; they are relying on a system. The overwhelm comes from trying to track it by memory. The fix is to get it out of your head and into a reliable place, a system, a map, clear labels, fixed homes for things, so you do not have to remember where everything lives. You just have to know where to look. That turns an impossible mental load into a simple lookup. Start small. Pick one area and give everything in it a clear, labeled home, so each item lives in one known spot. Once that area is trustworthy, do the next. You are not bad at this. You have just been asking your memory to do a job that belongs to a system. Build the system, and the overwhelm eases.