OMG I have arthritis

Lately, the weather has been super gloomy. It has been raining everyday! This is absolutely horrible for my knee! It just aches and aches and aches. I cannot fall asleep at night because of how sore my knee is. I'm pretty sure I also creak when I walk up stairs.

This is me on my good days.

At the ripe old age of 22, I am feeling much more pain in my knees than I should. And with the ease of internet search and my knack for over-thinking and over-analyzing (see definition for hypochondria), I came to three conclusions. I could have:

Worst Case Scenario: Bone Cancer. 

Why I could have it:

• My knee feels numb and weak. When I stand on my right leg, it's almost as if I cannot support my whole body. One of symptoms for a tumorous growth is numbness due to the compression of nerves or blood vessels, thereby restricting blood flow. 
• I have felt this discomfort for a really long time. Over the past few years, I have had these pains on and off. It's only been lately that my knee has been consistently sore ALL THE TIME. With bone cancer, the pain is not usually immediately noticed. When the cancer spreads, the pain begins to increase.

Why I probably don't: 

• I don't have a mass. My knee is sore, but I don't feel any lumps...but then again, not all bone cancers have palpable tumors.
• No fractures. Cancerous bones are weak and can break from small traumas or even just standing. I can still play beach volleyball and have not seen any breaks.

Fixable Diagnosis: Meniscus Tear ala Jeremy Lin.    

Why I could have it:

• I ski - a lot. A couple years back, I fell pretty hard going over moguls on my right knee. Only my right knee is this sore, so I'm thinking that there is a correlation. Sharp twisting and turning (as found in skiing and basketball) can be the root cause.
• My knee feels like it's not strong and I feel like it cannot support me. Many patients who have been diagnosed with meniscus tears report being unsure about the stability of their knee.

Why I probably don't: 

• As far as I remember, my knee didn't swell after my fall. I kept skiing the whole weekend. With an injury like a tear, there should be an inflammatory response.
• I can straighten my knee. For people with meniscus tears, the torn piece can sometimes fold up and limit the range of motion for the knee. Of course, when I straighten my knee, there is an audible and visible shift of the patella. This is very common in younger females, but can lead to the erosion of the cartilage...leading us to my next possible scenario.

Geriatric Disease: Arthritis.                                                     

Why I could have it:

• I am a girl. Women are more prone to be diagnosed with arthritis than men. In fact, 60% of patients with arthritis are women.
• My great-grandmother has arthritis. This is a pretty far family connection, but arthritis can be hereditary. 

Why I probably don't: 

• I'm only 22. While more than half of patients with arthritis are under the age of 65, I am WAY under that age.  

With my own search results completely inconclusive, I made an appointment to go see an orthopedic specialist and, lucky for me, he had an available slot yesterday afternoon. Talk about luck! Usually, making an appointment can take weeks and mine took mere hours!

Unfortunately, he asked me to come back to consult with a knee specialist. I won't know definitively what's wrong until Monday. But at least no cancer!!

For all you doctors and doctor's in training out there, what's your opinion? Do you think I might have one of the above? If not, what's your diagnosis?