I do that sometimes too, actually. Small writings are better than no writings :) Just try to relax and let it flow... think about the things which have been on your mind. Inspiration can come anywhere, whether it's: a person or situation you want to address, something that has been eating at your heart, a beautiful moment, a self-reflection, an epiphany, or just something you love - the possibilities are endless, and I'm sure you'll come up with something!
Anyway, looking forward to your future writings :)