This phrase is usually preceded by the words "I love you..."
The literal bushel and peck is this: "A US bushel is a measure of dry volume and equals approximately 35 litres, or 8 dry gallons. An Imperial bushel equals approximately 36 litres, or 8 Imperial gallons. A peck is also a measure of dry volume and equals 8 dry quarts in both the US and Imperial systems. There are 4 pecks in a bushel."
What it means in the figurative is kind of a mystery, I suppose it means you are loved a whole lot? Google searches didn't yield very many results. There was one result but the guy who wrote the blog was a bit, okay a whole lot, sexual so I've decided to just let that particular article float out there. Ha.