I don't lag, and my latency is green. Every game I join there is that slight delay and then the game starts. The game begins really laggy and people leave right away. I can't figure out how to fix this. The game was running perfectly fine about a month ago. If someone could help me with this it would be greatly appreciated.
If you join a game, anything that may happen apart from your lag is not your fault. If you host a game and people leave straight away, you need to open up ports. If it used to work, I'd guess that you have ports forwarded but your router changed your LAN IP address, which happens periodically if you don't set a fixed one for your computer. Check this thread for the solution for your hosting problem. If you indeed join a game then the problem is not on your end.