contra, you have my sympathies. Only advice I can offer is that with both DSs we found after about 8 weeks, they slept much better for naps if just put in their own cot, away from distractions like TV, and left to go to sleep without shishing, rocking or stroking, which just seemed to overstimulate them. Teddy usually cries for a few minutes before dropping off. You may have tried this though. Ted sleeps for 40 minute stretches in day. I'd love a longer lunchtime nap but I remember ds1 only managing that once older and using more energy with walking etc.
Wellie, big hugs to you, must be v hard for you.