Watch An Explanation Of Season 1 Of Stranger Things, In Case You're Still A Little Bit Confused
Unfortunately, it doesn't explain whether or not Barb's parents actually missed her.
There's no shame if things go over your head a little bit -- especially when science fiction is involved. There were a bunch of aspects of Stranger Things that seemed a little confusing, and other things that (hopefully) will be explained a bit more when Season 2 hits. For now, here's a video by YouTube's Alt Shift X that will help put a few pieces together a little better. (Even if you totally understand the show, you should watch just to hear the narrator say "laboratory" -- it's a treat.)