Hi - My PV2 has performed flawlessly since I bought it. I've been away for a month, so it hasn't flown in about 5-6 weeks. Took it out on a lovely morning today…and on take-off, it kept flopping to the left. No matter if I added power to either side, it kept flopping in the same direction. I'm very sad :-( What could be wrong with my baby? Thanks!