Can't even sleep well anymore, if I stick to holding is it possible to make gains too ?
Yes it is really exhausting to review the charts and if you this often you will really get tired of it. This is one of the reason why I can not do trading regularly. I know that clicking the buy and sell button will just take about a few minutes but of course before you buy or sell your coins you need to study what you are going to buy or sell.
Now for your questions of course holding is also profitable. It might not be as profitable as trading but it is safer and less time constraint.