Yeah, this whole stanza is a metaphor, comparing the singer's love to alcohol
Took you like a shot /
- probably means, got involved suddenly, and the feelings were intense
Thought I could chase you with a cold evening /
- generally, after you take a shot, you drink something more pleasant to wash the bad taste out of your mouth (the new drink is called a "chaser" because it "chases" the shot into your stomach).
This metaphorically might mean that the singer thought they could just leave (into the cold evening air) after they "took a shot" of this person's love
Thought the years would water down how I feel /
- when you "water down" a drink, you add water so that it takes less intense. Here, the singer hopes that time would make their feelings less intense