Chekhov Biography question

I have a question about Chekhov the physician. I've read that he considered himself a doctor and thought of writing as a hobby but I don't know if this is true. I've seen the following quote by him: “Medicine is my lawful wedded wife, and literature my mistress. When one gets on my nerves, I spend the night with the other. Neither loses anything by my duplicity.”

Can anyone refer me to a reference regarding this question of whether he considered himself a doctor who wrote or a writer who went to medical school to make his family happy.

Thanks.

definitely he WAS a doctor, i think.

in his biography i read:
... After he finished grammar school Chekhov enrolled in the Moscow University Medical School...

... Chekhov graduated from medical school in 1884 and he practiced medicine until 1892...

... Instead he turned back to medicine and science in his trip to the penal colony of Sakhalin, north of Siberia. While there he surveyed 10,000 convicts sentenced to life on the island as part of his doctoral research...


for more info please check out this web page:
http://www.online-literature.com/anton_chekhov/