a question about knee injuries

so i really hurt my knee yesterday. i felt it twist when i was falling and got scared because the way i felt it move i knew it could have been bad. it really hurt but i was able to walk around on it the rest of yesterday (with a limp, but still able to walk) but when i woke up today its basically dead. if i move my knee it just kills. it also feels stiff. do you think this could be a torn ligament or just a sprain? since i was able to walk yesterday i was thinking definitely no tear. now im not so sure. whats the best option for treating it? obviously have to go to a doctor if its torn but i don't know if it really is that bad. im going to europe in 2 weeks to start my backpacking trip and i feel like i could have just effed that up. if its just a sprain, 2 weeks of resting it up should be good enough to at least walk around on right?