Stress is a factor in dream recall. My recall will almost completely wither away if I'm under a lot of stress. And if you're conking out almost as soon as you get to bed I'm guessing your body needs sleep that badly. Maybe you should focus more on eliminating or lessening the stress in your life and getting adequate sleep before working on dream recall again.

But if you're determined to remember, try to adjust your sleep schedule so it's regular. Write even the smallest dream fragments and even the smallest lingering emotions from the dream.
Before you lay down to sleep tell yourself to remember your dreams. Just stick to it and the recall will come back eventually.

I dream in vivid colour as well. Most people do. It's odd that once upon a time it was thought that we could only dream in black and white.

The only time I've had a black and white dream was when I changed the dream scene to black and white so I could see what it would look like as a B&W photo before I actually took the picture.

Hope something here or there helps you get your recall back. Above all else stay positive and believe your recall will come back.