It seems to me that your problem is not inspiration but getting stuck in a rut. You get stuck in a rut because you buy the same ingredients all the time and that's all you have to fall back on when making lunch. Here's my solution. Take it or leave it. :-)

Find five different, well-balanced meals and buy all the ingredients. Then, put them all in a rotation system of five weeks. Using combinatorics there are probably 125 different permutations to which day of the week that the meal gets served. Make a chart calling eah meal 1,2,3,4,&5 respectively.
1,2,3,4,5 week 1
2,3,4,5,1 week 2
3,4,5,1,2 week 3
4,5,1,2,3 week 4
5,1,2,3,4 week 5
and now throw caution to the wind and mix the numbers up in a hat and pick them out randomly!
3,1,5,2,4
1,5,2,4,3
5,2,4,3,1
etc.
etc.
Serve shaken but not stirred! But, always, always remember to buy all the ingredients every week.