That's interesting you should say that. I have the same issue with memory loss and long term use of medications. Even after being off of it I still don't feel normal (whatever that is).
Working as intended. Making your memory fuzzy is part of how antidepressants are supposed to work. You're probably familiar with the expression "time flies when you're having fun" - positive memories are not as strong as negative memories. When you're bored or depressed, you notice every second.
Depression and anxiety can be tied to a lot of things. For some people, anxiety is caused by overthinking everything and constantly second guessing. A drug that fights anxiety, such as alcohol, will make a person not notice things like that. A slightly drugged person will go with their instincts and do what they want instead of overthinking everything. If your dosage is
too high, you might even start to miss important details. Can't remember faces, names, dates, keep track of money, etc.
Erasing memory is actually one of the ways to treat "shell shock" or post traumatic stress disorder. If your memory of being in a POW camp is vivid and feels like it happened yesterday, then minor things can cause a lot of anxiety. Things you interact with look and sound like things from the POW camp. Random objects bring back painful memories. Making those memories a bit fuzzy can reduce the impact they have.