Can't put alot of weight on Knee, Difficulty walking?

I own a horse and I was bringing him in from the field yesterday. Just as we got onto the yard a huge clap of thunder was right overhead and he spooked. He ran into me knocking me down to the floor. I Have grazes up my left side around my lower back area so I fell backwards onto my bum however my right knee is in pain!? I think what may have happened is when he has ran into me he has hit my knee with either his knee or his hoof (He doesn't have any shoes on so no metal came into contact with me). When I tried to stand up iimmediatelyafter I couldn't put any weight on it at all but 5 mins later i could walk on my toes of my right foot. I got home and had a warm shower and put my knee oon topof a cushion to keep it elevated also have an elastic tight bandage round it for support. I can put some weight on it but I wouldn't be able to stand on one leg as my knee would buckle underneath me. Should I go to the doctors or Hospital or is this just a small knee injury that a bit of rest would solve?? Thanks