I had my knee give way on the weekend and I heard/felt a snap- now I have pain right under the knee and across?

it as well, I can't wiggle my toes or rotate my foot up or down and while laying down raise my leg and much pain while trying to straighten my knee. I also have some type of fluid running down the centre of my knee. I am up almost all night for the last 3 days or so with just horrible pain. anytime I try to walk and straighten the knee go up or down stairs even sitting, while going to bed, doesn't matter pain is there. some bruising showed up after and redness over the knee cap. I have taken tylenol, ibuprohen, and t 3s as well as icing and putting the leg up. nothing is helping, pain is worsening.