Battle of wills

One of the hardest things is the constant battle in my mind between thinking about all the things I could do if I didn't have a baby and trying not to think that way...

And every day that goes well I feel a certain level of triumph, but the feeling doesn't last.  And I think, 'I can do this!' And then the reality of it only being one day, and having to live this same day over and over again for at least 7 more months...maybe more...is exhausting and crushing.  How do I stop thinking like that? Everyone says to not live for the future, but I can't help it.  It's constant.