Yes. Leverage and margin magnify your wins - and your losses. What many commenters here are describing is slippage - that's when a price blasts through your stop loss and it fails to execute on time or at all. If you don't have sufficient margin to support your trade, you'll get margin called. Another great way to be margin called is to not have a stop loss at all and the trade goes against you very fast and very significantly. When that happens, you have to add money to your account to cover the margin call and all open trades will be closed as well. A margin call is is the equivalent of Chernobyl or Fukishima on your account.
This is why you should use stop losses and never risk more than 1% of your account on a position. BabyPips has a calculator to set your position size based on risk %, your account balance, your stop loss size, and the pair being traded. The bigger your stop loss, the smaller your position size has to be. You don't want your stops too wide, because you're exposing yourself to large losses, but too tight a stop smothers your trades and leads to chopping up your account - "death by a thousand cuts."
You also need to watch your trades. I'm trading demos, but I've gotten quite a few losses because I had to to go to the bathroom, answer a phone or something else, the trade went against me and I was completely oblivious to it. I don't like swing and position trading for this reason. You can't watch trades overnight while you sleep and anything can happen - very fast - while you're out for the night.