Sudden appearance of symptoms after 20 months?

My understanding is that Chlamydia is asymptomatic but when symptoms do appear, they generally appear within a month. I have recently experienced symptoms and I am certain my girlfriend has not been with anyone during our 18 month relationship.

Has anyone noticed (or know of) symptoms appearing well after a year of contact with a potentially infected person? It has been over 20 months since I was with anyone else and unfortunately I have not had an STD test during that time.

I read someone else's message indicating other possible non-sexual sources of Chlamydia. Is there a web site or literature with more information? Throughout my readings on the internet I have not encountered such information. All resources lead me to the idea that direct sexual contact is the only way to transmit Chlamydia.