If you lie down and sleepiness starts to overcome you, abort meditation and go for a Nap. Best done between 12:00 and 16:00, with a clock to prevent sleeping longer than 1 hour.

100 Breaths

Lie down. Take 100 deep breaths. Count breaths as far as you can. If you get lost in thoughts, thats ok. If it is a bad or critical thought, switch to being grateful or think about a person you love.

Flower Meditation

Stare at a flower, she is beautiful. A thought comes up, is the thought more important than the flower? Go back to the flower.

And more

Experiment for yourself, what compination of breathing, controlling thoughts and relaxing muscles helps you. You can also turn it into a game to see how fast you get distracted, and if you want to push the upcoming thoughts aways, or explore them. Labeling thoughts and emptions is one of the strongest, if not THE strongest way to reflect and work with problems.