Yes, dream sign visualization can be successful. I would just focus on the one most common dream sign that you can visualize clearly. I have used it successfully, mostly during WBTB or just before going to bed.
On the waking life and sleep issues, I don't have a lot of experience or expertise but for sleep see if this article helps:
10 Tips to Reset Your Internal Clock - Sleep Center - Everyday Health (seems the site is not selling anything but ads)
On the waking life issues, you mentioned getting angry at yourself. Catching any negative thought loops can be helped through mindfulness and meditation. Try to not criticize or judge yourself, just try to catch yourself when you are not thinking or acting optimally…more like "I was thinking this way…ah...good catch!" Not "I was thinking this way, why am I always making that mistake." It takes time for sure and simple breathing exercises help also. You will notice your breathing patterns change when you are not at the optimal state. A simple one exercise to start with is breathing in goodness, and breathing out any negatives with a cleansing breath. It can do wonders.
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