Feeling Guilty

Who else has been struggling greatly with their pregnancy or have struggled in the past. I have two beautiful babies of my own and I am 18w pregnant with my 3rd. I am having such a hard time enjoying any of this pregnancy. I hate to admit that but it so true. Everything in me doesn't want to be pregnant. I just feel so overwhelmed by adding another. Also am super self conscious about my body and so desperately want to work on it and I can't right now. I hope this will get better. I feel so guilty for not enjoying this baby. Has anyone gone through this. Does it change. Is this normal