Haematoma?

ok so i have a tiny pool of blood under my knee, its half an inch i length, and really thin, and last night it was bruised, today it isnt, what is this? its sunday now 3:00 am and i cant sleep, i have a funny sensation in my- foot and there is NO ER or doctar available until monday. would appreciate some info or advice especially from real doctars or nurses-and if its really try to rephrase it :P