Should I see the doc AGAIN?

I was playing with my 150 pound Saint Bernard last weeken in the yard when she started to get excited and run around the house at full speed. She does this often....they are like short bursts of pure adrenaline. Anyway, normally she'll only come so close so I have to pretend to chase her like a game of tag, but I mistakenly took a wrong step just as she did, and 150 pounds of pure speed like a freight train barreled right into my knee. It was enough force to send to the ground, and I felt the pain immediately. I couldn't even stand up for about 30 seconds, and the pain was terrible. Once I was up, though, I could limp on it a little bit. I thought it was just a bruise and that it was fine and would go away immediately, but I limped on it all day and then for three days straight. After the three days, the pain went away, and I thought that was the end of it. Well, a couple days ago, I was at a friends house climbing the stairs and the pain came back. I only felt it when climbing the stairs, and it was hard to get up or down them. This time I went to see my doctor and he checked it and told me to ice it and rest it, ect and that it would be fine. Well, just yesterday I was feeding my horses and my dog did it again!! (She gets so excited, but her weight and size makes her destructive...) So she plowed into me again on the same knee. It wasn't as hard as last time, but it made it hurt much more. Today, I can hardly walk on it, and I can't bend my leg. Also, when I put my hand on my knee cap and move my leg, I can feel it popping and moving under my touch. I don't want to be a baby and have to go back into the doctor just to have him tell me the same thing, but it never popped/moved before. Could she have knocked it out of place? I can't kneel down or use stairs cuz it hurts too much.Should I see the doc AGAIN?
yes she could have dislocated your knee/kneecap. and Yes, you should go back to the doctor. You might get a brace this time.

good luk