Why does my iPhone 5S only connect in certain places?

I had my iPhone 5S Gold for about 3 months now. Prior to two days ago, July 6, i had no problems with wifi in my room. Yes, it was quite slow sometimes, but never unbearable. But starting from the 6th, wifi just stopped working completely in my bedroom only. I live in a one story house, so i didn't think i could be THAT far from the router but maybe that's the issue. It works perfectly when I sit in the living room which is right near the router. Also, even if I try turning on my LTE in my bedroom after being fed up with the wifi, it only connects to 1x, or 3G which are both very iffy and sometimes even the 3G doesn't work. It rarely connects to LTE in my room anymore. However, my Microsoft Laptop in my room is working fine. Does anyone have any solutions? I tried turning off my phone and turning it back on, switching off the wifi and trying to reconnect (many times my network wasn't even available anymore), forgetting the network, and things like that but still it doesn't work. Does anyone have a solution? By the way, I'm a teen girl who knows next to nothing about anything relating to technology, so if you think there's a problem with the router please explain it simply. (I'm also not sure if I take it into the Apple Store they would replace it, because my wifi still connects when you're near a strong connection but when i'm in my room it doesn't connect) Thanks