I am going through this, too, so I understand you 100%.
My DD starts next week & I have been a total basket case, an emotional wreck. I'm sure it has to do with the fact that she is my one & only & it's starting to look like we probably won't have another one. DH also has a 19 year old from a previous relationship, so he's fine with what he has.
I am also looking for a part time job, so I can still be around for her, so the thought of all the impending change is really overwhelming.
I got called back for an interview, and they wanted to do it on Monday, but that is the day DD starts K, and I know there's no way I'll be in the condition to put my best foot forward.
My plan is to TRY to hold it back until after I drop her off. I know she'll also be anxious, nervous, excited & I don't want her to freak out because I'm upset.
I guess I'm not much help, just know you're not alone in this. Hang in there :-)