Lag

Ok so I've been experiencing pretty bad lag recently, (on the lagometer it reads as a high block of red , entire screen and music freezes ,) aside from this I'm also getting the normal lag spikes I've always had. But today it's kind of escalated to the entire computer freezing randomly whenever I'm on multiplayer, I have to ctrl+alt+delete and cancel jk2 to escape it lol, as far as I know no changes have been made to the internet or the computer so I'm really stuck :/