I've been searched well within the country (probably 70 miles from the Mexican border) by some kind of border patrol/immigration officials, who randomly stopped

I've been searched well within the country (probably 70 miles from the Mexican border) by some kind of border patrol/immigration officials, who randomly stopped me and kept me there for over an hour. Their reason? My car was riding low, and looked like it might be loaded with drugs. Are drugs even that heavy? I had long hair at the time.