Stress about A-Levels I’m taking

No A-level is easy- psychology is certainly not an easy A*. I would focus more on what your strengths are, what you enjoy and find straightforward as every person is going to find different subjects easier, e.g. people in my class found a-level French okay but I found it impossible having found the GCSE way too easy, whereas I found english lit easy and others didn't. So basically, economics is hard but doesn't mean it will be too hard for you like whoever has told you that.
I would recommend dropping psychology (as you don't like it so much, and as it isn't objectively 'easy') however I have heard that further maths has quite a jump into year 13- people sometimes drop it at the end of year 13. Again, doesn't mean it will be too hard for you, but you ideally should have 3 A-levels in year 13 in order to get to uni unless you apply to a lower one which goes on UCAS points not grades as you could get in there if you aced two. So maybe explore with your teacher how you both think you would find A2 further maths or swap psychology to something you like more if you really want to get rid of it so you could do four AS and drop further maths? Just ideas. I hope this helps