Performance issues with new version of Unity

Let me preface this by saying I usually put off updating Unity, but I updated it yesterday. And until I updated it, my game could handle updating around 100 objects and ran at 60 fps with no issues. Now it's weird, because if I break probably 50 the fps drops, and at 100 it's running so poorly that collisions cease to happen. I'm not really sure what to do about this, it's a 2D game using Sprite Renderers and 2D rigidbodies and colliders and such, so maybe something went wrong with the new additions? I dunno, looking for help.

Please ask for any clarification you need, I'd be happy to provide more details.