When pine shoots go floppy, there can be a couple reasons.
First and foremost: do they feel rigid? Not like a deflated balloon animal, but like an inflated one; do they bounce back when you move them from left to right? If so, that's a good sign. It's probably normal behavior. We need not look into a cause, but it's likely a little excess of nitrogen.
If they feel droopy, and don't bounce back after you push them left or right but they just dangle a bit, or feel floppy to you, then it's time to water. This is not something you want to see happen every day, so it's time to use the chopstick in the soil to check for moisture on a daily basis. I've had it happen a couple times, once or twice is not a problem, three times could mean the root system got so dry that it died.
If it's watering related, please report back tomorrow after a thorough watering, they should be back upright again. Let us know if that's the case!
If it's not watering related and they still feel floppy some six hours after watering, please report back for further investigation.