I just wanted to tell you (with firm authority
) that kids are insulated by nature's narcissism and will have absolutely no memory of you crying. You will not damage them.
Secondly, I don't believe your Mum would tell you you just have to 'get on with it'. She would know the utter pain you are going through and want you to do whatever you could to be kind and loving to yourself.
Thirdly, keep getting signed off. Believe me when I say you will never be glad you went back too early.
Fourthly, is there a 'place' where you feel your Mum around you the most? When my Dad died I feel really close to him in our local shopping centre and used to find it weirdly comforting to go there to think of him.
Fifthly, talk to your Mum in your head, tell her how you feel, 'listen' to her voice. My Dad had a really inappropriate, dry sense of humour and when I had head conversations with him, it would make me laugh.
Keep going, minute by minute. I hope I can be half the Mum your Mum was, she should be an inspiration to us all.