Open up to the challenge
All of what they said.. but very importantly, something else too.
Remember YOU WANT TO DO THIS.
YOU CAN DO THIS
THERE IS MORE SPACE IN YOUR BRAIN
YOU ARE HAPPY TRYING YOUR BEST
If you think you are fighting and struggling.. you'll do less well.
Open up your mind and reject all negative concepts about study.
The other stuff in life can wait till after you did what you need for your studies. Its a bit like tunnel vision, but it is a tunnel with a wonderful destination at its end...your best future.
You could even put a paper on the wall you face, that says
"I WANT TO DO THIS"
And remember to take small breaks to stretch your legs and relax your mind.. just don't let those breaks stretch too long.. 10 mins per hour is more than enough.
If you went to two hours without a break then take a half hour to get back to optimum study power.
And good luck with your efforts