If you have trouble going back to bed I recommend you try something called the "progressive muscle relaxation technique" (there's some instructional videos on YouTube).

Basically the technique involves tensing your major muscle groups for 10-15 seconds and then releasing. For example tense your calves very hard for 10 seconds and let go. Then tense your quads for 10 seconds and let go.

Keep doing this until you've worked all your major muscles and you'll feel a lot more relaxed and will be able to fall asleep much easier.