Updating Unity Caused Severe Drop in FPS

So I’m working on a simple 2D game. Everything was going fine, it was all running well. I would build the game and get good FPS despite my crappy computer. Recently, I decided to update to the latest version of Unity 2019 from Unity 5.6. Now, the game runs horribly despite little to no change to the game. I’m getting extremely low FPS and choppiness and I have no idea what’s causing it. I’ve done quite a bit of optimisation but it hasn’t changed it a bit. Anyone know what’s wrong?

There is really a big gap between 5.6 and 2019. I can sugget you to go back to 5.6 and build the project with that version, than start working on new projects on the 2019 one.