Unity lagging after update?

I've been working on a lightweight game with some friends. Today I updated Unity, and after about 30 minutes of loading time, I was able to edit my project again. But all of a sudden, Unity is being very slow. I try playing the game, and it is running at about 2-3 FPS. The current editor mode is DX11, but I tried forcing it to OpenGL and that only made it much worse. My computer should be able to handle it; I have a GTX 1080, 32 GB of RAM, and an i7-8700K. Can someone please explain what is causing this, and how to fix it? Thanks in advance!