Selling to buy back isn't a bad idea, and whenever you want to buy back there will be bitcoin to buy back and not as if the bitcoin is going to exhausted such that you will not see again to buy back, that is why there are exchanges out there who will always have Bitcoin to sell to you if you want to buy but if you must follow up with this strategy, be sure to keep tabs with the chart so you see the buy back opportunity and buy.
This isn't a financial advice though but make sure to do that which you find okay enough to do and avoid FOMO so you do not make wrong decisions because you are agitated or under pressure to meet up with price as it moves.