Strange Happenings After Trip to Las Vegas

I hope to hear from anyone that may shed some light. Myself and several friends went to vegas to attend a wedding. That evening 4 of us went to dinner together me and just one of my friends at dinner shared the shrimp, so he and I were the only ones to have the shrimp. We all returned to our separate homes on a sunday, monday rolls around and that afternoon I knell down by my pool and as I stand up my knee gives out and with great pain I try to walk. I have had some popping in the same knee in the past months. The pain and swelling continues each day. Then I suddenly have swelling and pain in my right side neck lymph node gland.

Now the strange part my same friend that shared the shrimp with me had the same exact things happen to him, only one difference both of his knees where in pain. Could it be possible that there is a link to what has happened to us?
Please share your thoughts or ideas, im thankful for your time.

Sincerely submitted,