It depends what you did use! I sow several hundred seeds every year and have never bothered with "seed compost". I always use multi-purpose compost and just make sure there aren't any lumps.
I stumbled across this, it's a video by Alys Fowler on how to make a light reflecting box for seedlings grown in poor light levels. Watch out for the teabag tip, I'll be using that for sure.
I think the compost was too dry if anything !
Compost was last years
Will try and build the lightbox to help.