Feel detached from child

Well I'm 34 weeks with baby number 2. I have an amazing daughter who just turned 4 on Tuesday. I love her sooo much and would do anything to make her happy that is in my ability to do so. Well since I got pregnant I feel so detached from her. Like I dread wakingn in the morning because it's another day of having to play and care for her when all I wanna do is sleep and relax because I'm so exhausted. She is going through a phase where she doesn't listen at all to me and i feel like all I do all day is tell her "no" or to "stop that". It makes me want to cry at how distrespextful she can be towards me now with this attitude. I can't wait for bedtime so I can just sit down in peace and go to sleep. I have gestational diabetes so that's made it even worse and servere SPD that physio has not helped so I can't even play with her when I do feel less tired because of my pelvic pains. I just wanna be a proper mummy again and not feelthis way. I'm not depressed at all im just tired physically and mentally. 

When she is a sleep at night I just wanna get get in bed with her and hold her and cry because of how bad I feel because of how crap her day must have been with me being so tired and not playful. 

I know when baby is here (getting induced in 3-4 weeks) I'll be able to be a proper mummy again but still I just want to do that now while I still have the chance of it being just me and her. I mean at night for bed she wants me to lie with her till she goes to sleep after her bed time story but I can't because then she will get used to it again and then when baby comes I won't have the time to lie with her for 15-20 mins till she is asleep even though Id love to just lie there hugging her and smelling her smell. 

So am I the only one or is they anyone else out there the same?