You encountered such a situation because you refused to follow the advice of your friend who warned you not to put all your eggs in one basket. Ponzi or HYIP is not good at all. What they do is entice people with outrageous profit. You can make money from it and still loose all at the end.
In my opinion selling or buying bitcoin is personal decision. I if want to buy or sell bitcoin I will never ask people what should I do and now you have sold your bitcoin, now what are you asking for? Did you want to waste other peoples time and want to collect different opinions about your decision? Ok you did very well bitcoin is for overcoming financial problems and you dis the same.
Yeah it is right especially in these days while the price is low. These days are for buying and investors want to buy more and more due to low price because they also sure about the future and will make handsome money after some time. Although the price is not increasing for the last several months but this situation will not last longer and good days will come soon.