Yeah, you're right crypto can easily be manipulated by people specially those have big influence in crypto, however, you have you're own decision if you want to sell everything, so next if you want to buy coins just make a research first.
I don't agree of selling everything specially when I bought it in high price compared to current price, if it's really needed maybe I will sell half and I will hold the other half hoping it will increase again soon.
Yeah, I would never go all in or all out ever. Market can take reverse gear any time and you need to be ready for thay so that you could take desirable step at that time. Selling everything was not a good decision because if market has come down then surely it would go up too.