I know that feeling very well, my first bitcoins I had in 2016 and unfortunately I sold all of them back in the days. It was my biggest trading mistake to not stick around. From time to time I think about how many bitcoins I had and how much money that would have been today. Such a thinking is of course not really fruitful and only makes me feel mad. It's hard to accept that we can't turn back time, the only thing we can do is learn from our mistakes and not repeat them. I am also happy that I am invested in bitcoins now and I am never going to sell all my coins again. Don't make the same mistake like me guys and stay invested, otherwise you are going to feel bad in a few years.