If I put it in standby for a few minutes, it'll come back up to a black (>20%).

In a few minutes it'll drop under 20% and I'll get a red battery icon. For example, right now, I am in the black. I get a popup of low battery dropping under 20% every time it does that. And then with heavy use and a bright screen setting (I was outside a lot today) it still some times shows a black battery icon and then alternates between black and red. Today, I got up at 6 and got my low battery warning at around noon with light use. With the exception of one day, it never went completely dry even if I got the warning before noon (I usually get up between 6 and 8 every day and go to bed around 11). It seems like after a couple of hours of normal use (some messaging, email, weather checking, maybe surfing the web a bit between classes) it give me a warning that I'm at a low battery life. So the last few days I kept a close eye on it (I charge it overnight every night). So within the past month or two, I feel like my iPod Touch (5th gen) is getting very crappy battery life.

Half-Life for ipod instal