It's only March 31! How long have you been having nice, warm, sunny weather? I mean like 70° sunny days? Probably not quite long enough for the seeds to know it's time to wake up. Give them some time.
Every seed has it's own requirement for germination, and when that's met, they pop. I only have a couple of sprouts in my forget-me-nots. I never give up until the end of May. Some people hold on to them until the next year, and they sprout.
Karen