Is there anything I can do for my laptop battery?

I have a Samsung QX411-W02UB. Had it since late 2012.

I loved the long battery life in the beginning but then I noticed a decline. Now, the decline in battery life is so obvious that I feel like something’s wrong with it, or at least something is wrong with how my laptop is estimating my battery life.

I tried calibrating it. Letting it die and then charging all the way and then seeing if it estimates the battery life better. It doesn’t. It falls rapidly. In the span of like barely 10 minutes it says it’s 75% then 60% and literally right now in the time it took me to start this post and type here it went down to 55%.

BUT THEN. It goes back up a little bit. The percentage keeps dropping but the estimation in remaining time keeps shifting up and down. It’s all very confusing.

The thing that sucks about this laptop is that you can’t remove the battery.

I have no effing idea why I made this choice to begin with when I got this. I must have not been paying attention.