Internet is very laggy but not slow?

[sloth]

Recently my internet has been extremely laggy, yet things like Youtube videos and other websites have been loading fine as normal, the only problem I'm having is while playing video games I will get kicked from the server, or it will simply be laggy. When I've tried to host lobbys I usually get kicked for making everybody else in the game lag, or I make the other people in the lobby get kicked simply because they lose connection to my host because of the lag. I'm not exactly sure why this is happening, my internet is not capped because other things are loading fine. This has only started happening recently (started about a month and a half ago), at first my internet was simply going slow, I waited a while and it started to speed up and return to normal but now it's very laggy. Is there any ways to fix this or does anyone know why this is happening?