Thank you everyone for the general encouragement and positive thoughts being sent this way 
themidwife I am due up at hospital as usual first thing tomorrow, so will take a MSU with me and see what they say.
whitesugar thank you for sharing your experience. It made me realise that I cannot imagine anything WORSE than twunt playing the doting dad in the delivery suite, and making me feel even worse. I don't owe him anything at all so I think I am going to stand my ground and ensure that he is not there to detract from the process, and spoil my memories.
Going to see if a warm bath helps now. Earlier on I went in the (deep) paddling pool with the DCs - they have an inflatable ring thing and so even though I am not allowed to get my PICC line wet, I decided to risk it and sat in it. The water was really quite chilly and I laughed and laughed as DS pulled me round in the ring. He said
"I haven't heard you laugh in ages mummy"
It's true
I have simply been surviving for months and months, and trying to make sure they are happy and having fun, but I haven't at all been having fun. They were both so pleased to see me smiling and hear me laughing, although they were not so happy that I didn't stay in long, but I had to try to be a bit sensible re the line.
I hope that I find my laugh again on a more regular basis soon.