Extreme Memory Loss - 15 years old

I'm 15 years old, and I have been getting bouts of memory loss. Recently, I cannot remember things that I should be able to remember - only to think of them after like 10 seconds or more when I should be able to remember them instantaneously. Before, I don't remember having memory problems like this. Only, in the past couple of months do they start happening.

The only reason that I can think of that may account for this is sleeping the past semester every night at 3-4am and getting up at 7:45am. I recently began sleeping more normally, but I show no significant or immediate signs of memory restoration. I'm really scared, I don't want my brain to lose IQ points as I need them to do well in studies - I heard that brain cells are only depleted and do not make new ones. Have I killed off my memory/brain cells by sleeping so late? And because they don't grow new cells, I'm stuck with a memory like this?

[DrNoopurMD]

Hi,

Thanks for writing in.
Please relax you cannot kill your brain cells by lack of sleep. I think lack of sleep and anxiety are the mainly responsible for the lag in memory that you are experiencing. Keep yourself relaxed, eat well, sleep for at least 8 hrs and make sure you keep yourself physically active.
Take care!