At a loss after enrolling into PhD programme
Well.. WELCOME TO A PHD! 

Sadly all that work is normal and it's only getting worse. Doing 4 essays overnight is not uncommon, research will be tossed away by professors, you wont have time for friends or family, and your health will deteriorate and you will loss/gain weight. All unless you can somehow automate things (a dictation software helps A LOT), or you can externalize the homework, which is not ethical and might not even be legal. 

Oh! and your research and enthusiasm is meaningless. You could have the cure for all types of cancers but if your references are not in proper APA it all has no value. Thats academia. You are not there to research, you are there to document properly a research. (Im already expecting this answer to be downvoted a lot as it touches many sensible fibers)  

In my PHD I ended up with a horrible lower-back damage that send me to the orthopedist-traumatologist, a friend got facial paralysis, around 30% of those who entered dropped, and the ones who managed to  take  it lightly was because they didnt have much responsibilities, work in bureaucracy and had people to do their HW for them, or similar.

A PHD is a big commitment that frankly isn't worth for many people, but a lot of people realize it only after enrolling. But hey, if you are stubborn then you already have the proper character trait for it, you just need to accept the cost of opportunity, which is that you have to set aside basically all else besides work.

If you are ready to drop, perhaps you should enter an MBA instead, the workload is almost just as bad but at least you don't have to worry about research and it's not so academically oriented, which might be more motivating. Also speak with your professor and negotiate sending your HW by mail as being in the lab is an impossibility for you, or at least negotiate only going  a couple days and the rest work at a distance.