Hmm... Strange.
Even though I have used Lightworks, I haven't tried speed-changing anything yet. But something similar happened in Final Cut Pro (which I use at school), where the clip is slowed down but still has its original length. It's supposed to double in length. I noticed that only happened when I had more than one clip in the same track. When the clip I wanted to change was the only clip in the track, it was fine. It might be similar in Lightworks, so try creating another video track. Do your speed-changing in that track, then move it down to your main video track. Do that for each clip, then delete the second video track when you're done.
Not literally dead, just no longer interested in Lego or animation.