To the OP, it's hard to answer your question without having been there, but you are correct in your implication that the information you received was not accurate at all. It's impossible for us to say whether you simply misunderstood what you were told, or whether you were told this on the basis of other information you have not given us, or what exactly happened.
Maybe try this again. Go back to him in confession again when there is plenty of time to talk (not before Mass), and just say you are confused about what he explained about these types of sins, and ask him to give you a comprehensive explanation of this subject (impure looks) and how to know when this type of sin is mortal or not. Ask him any questions you have about what he says, including the questions you have posted here.
If what he said still doesn't sound right, then maybe give us an update. I would also recommend writing in to True Restoration or Most Holy Trinity Seminary and asking them to explain these principles to you; they are well-trained clergy and would give you correct information.