Galaxy Note 3 battery and charging problems. Help?

[Khadija Nisar]

So I got my Samsung Galaxy Note 3 around a month ago. The battery was fine early on, but then I woke up one day (I had left my phone on overnight charging- shouldn't have, I know) anyways, the charging was really low. This happened the next day too. Then, yesterday, it was 77% when I slept. I woke up to it being 17%. I plugged the charger in later, but the battery would keep lowering. I put it on overnight charging again today, and the battery had fallen from around 40-50% to 12%. Shouldn't it have been increasing? I came home and the battery was 2% so I obviously put it on charging again but the battery said 0% (literally) before the mobile powered off. It's been an hour since I last plugged the charger in and it's still 1%. I am so freaked out rn, can someone please help.
PS. Sorry for ranting on like a lil child and not using big hardware-y words, I'm just so friggin' scared.

 

[Rukbat]

I had left my phone on overnight charging- shouldn't have, I know

There's no problem with that. Charging stops when the battery is fully charged. You can leave the charger connected for months.

I put it on overnight charging again today, and the battery had fallen from around 40-50% to 12%. Shouldn't it have been increasing?

Are you using the charger it came with? Install Galaxy Charging Current Lite and see how much current is charging it - it should be around 1200mA.

I came home and the battery was 2% so I obviously put it on charging again but the battery said 0% (literally) before the mobile powered off. It's been an hour since I last plugged the charger in and it's still 1%.

The fiorst hour or so, it's not charging, it's what's called pre-charging. Leave it plugged in for at least 24 hours.

While it's charging, read The Care and Feeding of Lithium Polymer Batteries.

If it still doesn't behave, it's still under warranty, so bring it in for repair/replacement.

 

[Khadija Nisar]

Yes, I am. What were those little thingys that came with it, I meant to look it up online but never really had time, mehh. The reference shiz is 350mA and the maximum is 460mA. Is there something wrong with this? And do I have to keep it powered off while it's charging cos idk that's kinda hard to do.
I need it to behave since a family member brought it from Dubai and I don't have the warranty thingy with me rn.