Numb leg, stiffness, ice cold feeling, terrible pain

[celticerdlok]

Hello everyone! I would be grateful if someone could enlighten me on this.
I have been having this awful condition for about 3 weeks now. I had a sciatic nerve problem in my right leg which prevented me from being able to sit for prolonged periods of time. 3 weeks ago in class we had a very long lecture that went on for 2 and a half hours. Because my right leg was sick at the time, I decided to spare it from too much pressure and pain and chose to sit on my left leg. The chairs had a very hard wooden surface.  What I did was lean on to my left leg, sitting on my left side, particularly on the ischial tuberosity area, also referred to as sit bones. I basically placed most of my weight on my left buttock sit bone area. During that sitting, it immediately started a deep burning pain in the sit bone area and side of buttock. I felt the pain and knew it caused discomfort but I kept on sitting because when I tried switching over to my right leg it would get all numb and painful, so I was too afraid of doing that. I more less sat very painfully on my left leg for 2 hours tops and then during the other classes I also had several times where I would place more weigh on my left side bending my back towards left and feeling that same pain, although during later lessons I wouldn't put as much pressure on my left leg as in that long lecture that went on for 2,5 hours approx. Anyway, when I got home, I felt that something was wrong. My left butt side was very painful and sore. I felt pain emerging from deep tissue and that was when the numbness and tingling also started. My symptoms are burning transient electric pains, numbness in the butt area, almost completely numb to touch, leg heaviness and major stiffness feeling, major butt and leg weakness, motor weakness, leg pain, sensory deficit, numbness all across the leg and feeling of wearing high tight socks all the time, tingling and electric sensations, constant rushing tingling feeling all the way from my left buttock to the tip of my toes, my toes and foot are ice cold to touch, like a menthol feeling really, dead leg feeling, coldness from the inside feeling etc. My leg feels dead and has a constant tingling/burning/pins and needles sensation. As if you were sitting on it all the time. I also get major leg cramps and my leg gets tremors and is shaky all day long. I have very bad weakness and I limp as well. Is this muscle or nerve damage and if it is, should I go to a doctor to get an MRI, EMG etc.? It has been getting worse and worse, especially due to the fact that I have a heavy college load at the moment and a lot of sitting at school on hard surfaces and sitting at home is almost daily and for prolonged periods of time. I have tried using cushions but it doesn't really help. Tell me, have I done some permanent damage to my leg because it sure feels like it. I have never had anything like this before. My left leg was perfectly healthy before and I never guessed I could damage it in this way. Make it hurt for a few hours yes, but not like this. Is this neurapraxia, axonotmesis or neurotmesis? Has it something to do with circulation? What should I do? I am afraid that even if it has a chance of healing it will not because of all the school sitting going on. Give some advice and help me understand the mechanism and severity of such injury.
All the best,
Nathalie (in a lot of pain)