6 weeks and fed up

I'm 6 weeks 
I am so so so tired. I can't sleep though, I feel drained, I'm opening a new shop in a few days and there is so much to do, I can't ask others to do more as only me and my fiancé know about bump. I just can't concentrate on anything, I have a little boy who is nearly 2 and although he is a nursery half days I'm exhausted running about after him. 
Also on a separate note I have found I cannot lie comfortably on my front in bed which is my preferred position, I know it's not ideal and I should be on my left but I'm desperate to sleep, I have a REDICULOUS bad cough at the moment too and can't take any medication for it 😫😫😫