Is my 35mm camera film ruined?

Sorry, happens to all of us sooner or later, learn from your mistake, get out there and shoot more, make more mistakes and learn more. (Been there, done that and about a hundred other mistakes you haven't made yet, like walking out of the darkroom with an unwrapped stack of paper in my hand.) Note that film is very sensitive to light, just a tiny bit of light for a very short duration will cause exposure, the conditions you describe cause a massive OVER-exposure.