Game issue while playing Sejuani

Hi! I am playing League on a Macbook (I don't know if that is part of the issue). Almost every time I pick Sejuani, after 2 or 3 minutes I seem to disconnect, but I'm still in the game according to my premade. I move around, but I don't see when I cast spell, I see everyone, but they glitch. I can't see jungle camps, too. My premade says he sees me do everything, so it is not a connection issue (and we talk on Twitch so i'm connected to the internet), I think. Restarted my macbook, the game and nothing works. Thanks in advance for the help.