I did the same as you. Before visiting Canada I visited the USA for 10 days and came back to my home country. I fled Canada from my home country after one year of staying in my own country. Claimed Asylum in Canada and just because my situation changed I withdrew the claim and back to my country. I got back my submitted passport with a valid US visa. I have the same question as yours "My US visa is still valid or revoked?" I am happy that I got you in almost the same situation.I did not enter from usa I went To usa from from holidays when I finished my holidays I went back to my country then problem start in my country after few months I came canada so I don’t come canada from usa man I fly direct from my country to Toronto airport .