New here, Lost and depressed!!!!

I worked for many years as an adult probation officer for the State of Texas but quit about five years ago to help run a family business and help take care of my brother's child who was in a terrible car accident that left him a quadriplegic.  We live in a VERY rural place in Texas where resources are scarce and after months of trying to find help, my brother and his wife had given up and resigned themselves to taking care of him alone. (my brother was still working and only had 4 years left until he could retire.)   This past summer, circumstances changed and I became free to once again join the working world.  There are even less jobs in our rural area than there are in the city, so I decided to apply to an accelerated, hospital based nursing program that lasts one year.  Nursing is one of the few jobs that is plentiful here.  The program only takes 70 people and they always have 300+ applicants. The admissions process is long and difficult but I got in!!!!!  Classes started in January 2014.  I have always been an athlete, ridden horses, driven tractors, worked at hard farm and ranch labor, you name it.  There was nothing I thought I couldn't do.  Just after Thanksgiving, my hands started to ache very badly at night.  I attributed it to working hard and tried to put RA out of my mind.  You see, my father, brother and sister (who are 11 and 13 years older than me) all have RA.  By mid December both hands were so swollen and sore that I had pretty much lost the use of them.  I went to a rheumatologist and of course, I was diagnosed with RA.  I was put on methotrexate and mega steroids so that I could gain the use of my hands to start nursing school.  The disease came on like gangbusters.  I went ahead and started nursing school on January 15.  As of this weekend, I have an "A" average and am doing well in my hospital clinicals.   I am however, DYING.  School is 8 to 10 hours a day and then there are 3 to 5 hours of study at night outside  of class.   The stress is HUGE.  Making less than 80 on anything can get you kicked out.   I need to work and I don't have a plan "B."  I am not so disabled that I can't work and I can't afford to go on disability if even if I could get approved.  Last night my chest started to hurt.  I don't know if it's the RA affecting my heart or the stress!!!    I am terrified and I have NO idea what I am going to do.  I am so exhausted that I can barely put one foot in front of the other.  Any suggestions or words of encouragement would be GREATLY appreciated!