Welcome amohonour!
That's a tough question, depends on your strategy. Exits are very important. Do a search via the search tool in the toolbar for 'exits' and you'll find lots of tips. If you're losing sleep over it and you've made a profit maybe it's time to sell before it falls further, but then again this may just keep going. Always good to have a plan before entering and then stick to it. If it isn't good then change the whole plan and apply it consistently, if it doesn't work again keep fiddling till you get it right, but the market will only give you so many goes at it. Good luck!