Self lubricating

Me and my boyfriend have never really needed to use lube as I get turned on pretty easily when I'm with him. The other day we had sex a few times throughout the day (about 4/5) the 5th time we tried I was as dry as anything even though I was extremely into and excited for what we were doing...just wondering if it's normal for girls to, I guess you could say 'run out', if they've had too much sex in a small timeframe. Please comment!