Helloooo. 
So, I just lost from a recent long USDJPY position. 
I’m thinking it might be because my stop was too tight. And now I’m thinking it’s still very likely that price will go up like I initially predicted so I’m considering opening another long position, but this time, with a wider SL. What do you guys think? Is this something that you’ve done in the past? 
I also lost a long USD/JPY position, and it was at one point a good 120 pips in the green. Then plummeted like a lead balloon. I have since learnt that this was due to some fundamental news that I wasn’t monitoring.
I don’t see any reason why you shouldn’t go long again as long as your strategy is telling you to do so.
You should be able to determine if it was in fact your SL getting hit, and whether it was too tight or if a giant wick stopped you out.
It’s happened to me quite a few times. Smart money has a general idea of where most retail traders will place their stops, especially around key price levels.
I’ve done that many times but it’s important to reflect on your previous trade and analyze what went wrong and why you lost.
I think if you have confirmation methods and they’re saying yes, you can definitely go in again!
Yes, if trend-following and the trend is continuing. Sometimes a little delay or a favourable close or a little further price movement is nice just to get confirmation of continuation. for a similar benefit I use entry orders rather than buying live.