Unity game started running slow

Im haveing a problem with the unity game…Just yesterday it was running really good, now today I only have a simple walkway in the scene very low poly. And the frame per sec is like 2fps. and before it was 35fps with a big forest with over 1thousand trees.
what is going on!!

I wish i could put pictures but for some reason the unity site is glited when I upload a pic I cant put accept!

Check for debug functions presents; they can really slow fps… once i had same problem, forgot that i added debug.log =)

it might be that your computer is low on memory.

sadly you are going to have to be far more descriptive
there are litterally thousands of things that can tank frame rate

and thousands of things to fix it

35 fps is kind of low
my comp is 4yo and I try to keep frame rate at around at least 50 fps (and that is with some HEAVY code running with lots of assets)

if all you have done with project is purely art and no code
then it could be that you arent batching enouch draw calls
have too many colliders
have to many meshes

but also framerate can be influenced by what you are running in addition to unity
if im streaming a video in addition to playing a unity level, framerate is affected