Thank you all so much for your suggestions - I really appreciate it. I am seeing my doctor tomorrow and will chat to him about it and find out what options (if any) are available to me. Fortunately my DH has a bit of a work break at the moment (he works for himself), so he has been getting up to DS at night and letting me a have a bit of a sleep in on the really bad nights.

For those of you also suffering, I hope you find a solution and get some well-deserved sleep x