I have recently received two lovely little books - The Blessings Book and The Blessings Book of Marriage.
These are both pretty little hardbacked books. The Blessings Book is currently £7.99 and the Marriage one is £8.99 from the website at http://www.theblessingsbook.com/
The idea is that each book has lots of beautiful sepia pictures together with plenty of spaces for you to write down all the little things that make you happy on a day to day basis. Maybe someone pays you a compliment or maybe your husband buys you flowers - you can write down what happened together with how it made you feel at the time. Then, when you feel down, you can read through your book and remember those happy feelings to cheer yourself up!