I'll tell you something else too. When you have a baby your life is different than before. It's not worse, it's different. You need to think about the things that are important to you and to your baby and how best to negotiate that. Some days you can go to the gym and sometimes its just not the fuck worth it.
Or, to put it more gently, what "Sarah" said in her comment.
Also, it is very likely you can get more than 4 hours sleep when the baby gets here. I know some people don't but I do know that you, K, can nap during the day which means that even if your baby is a bad night sleeper you can nap when your baby naps or hangs out with Appleheart. So soon enough you will be back on the treadmill of life and of running.