Psychology or History?

In my school if you're an average student you take 3 as levels and continue with these 3 in year 13 but if you're slightly above average you take 4 as levels and continue with 3 in year 13. I was given the option of doing 4 as levels and i ended up choosing Bio, Chem, Psychology and History. Now it's February and we've just been given back our mock exam results which i didn't do too well in ( I got B,C,D,E). Most of my year failed the three sciences and maths. Now my head of sixth form is pestering me to get rid of one a level in the middle of the year to make the workload easier, which i think doesn't make any sense. I really don't want to drop any of these subjects but if i really must should it be history or psychology?

P.S sorry for the essay

Purely depends on what career path you want to follow.
I might be able yo help if you tell me what you want to be.

I am not exactly sure yet but i know i want to go down the science route. I have been thinking about either pharmacy or molecular biology.

If you want to go down the science route, I think you should take up psychology and drop history. I am basing my opinion on the fact that history has nothing to do with science and psychology is quite related to the career you might want to pursue. But another side to this argument is that only take up psychology if you think you'll enjoy it because you don't want to study something that you dont enjoy, for two years because this would greatly affect your grades and maybe uni choices . A good way to do this is to look at the specification of the subject and the specific board that your school is doing.
Hope I helped