VB,

I have dreams like that too. I think your line of thought that they are anxiety based is spot on. It seems to be like that for me when I am the most stressed, so that makes complete sense.

Something you can try is doing a short bit of meditation right before bed - in your head repeat a mantra such as "I will have good and peaceful dreams tonight" or "my dreams will be soothing" or something like this. Spend about fifteen minutes just relaxing yourself and thinking of good dreams.

It is likely that you DO have good dreams as well - but because they are likely not as jarring to your subconcious, you are not remembering them.

In this case too I would reccomend keeping a dream diary by your bed and writing down ALL details - even the ones that seem like they would not matter - like if you see a red pencil in your dream, it might not seem significant, but write everything down to the smallest detail. This can help train your brain to remember all of your dreams, and although yes you will remember the bad ones still, it may also help you work out where they are coming from.

Also, if you wake from a nightmare, after you finish writing down the dream, get up for ten minutes or so. Just do something - get a drink, watch ten minutes of television or read ten minutes of a book. This will help change your mind from focusing on the dream and may prevent you from falling asleep only to have a nightmare again.