Ah, unfortunately I had the same problem where my potato here couldn't really handle the game properly, couldn't play for too long without getting dizzy, unfortunately. Optimising 3D games is tough - I actually don't know anything about it myself (3D is a bit outside my comfort zone and I have no experience with Unreal engine either), but I do know that it's very common to see unoptimised 3D games, even from more experienced devs.
What I did see had some promising stuff, the environment seemed to be designed with thought put into it, and the game overall was looking good. I also had no obvious bugs like getting caught on collision or the like, which is very good for a beginner!
The monster did catch up to me, but nothing happened there - is it not implemented yet? Or was it a bug I stumbled upon?
Good job, keep on creating, and you will only improve! :)