9 Months of Crazy!

So my little guy is 9 months now and is as active as the day is bright. My gosh he seems to not stop not even to take a nap. People told me that this would be the hardest job I would ever love - well they were right. I love being a mom and a wife and more then anything the idea of making two people as happy as can be just by being there for them is amazing.
I have been blessed to be able to stay home with the little guy and to help guide and nuture him as he learns to walk, crawl, talk, eat different foods etc. But I think that sometimes we forget, as moms, that we need mommy time. Time to think, read a book, drink a hot cup of coffee and even just watch some TV for an hour or so. This may come off as being selfish but sometimes I just want my son to sleep for longer then an hour so that I can read my book or just sleep. Sometimes at night when my husband comes home I want to just leave them home and go off on my own for a couple of hours. Is this wrong? I mean my husband works 10 hours a day and its not an easy job. But neither is mine - I mean I am not playing all day and I am not able to just take a break when I want.
But sometimes when I am thinking about this and feeling like this I feel like I am being a bad mom or wife. I know that many women go through this but I am not many women I am me. I think that sometimes I need to be more thankful - But where do we draw the line of being selfish and selfless?
But I know that no matter how I am feeling and no matter what the situation - I love my job and my life. I love my husband and son more then anything and I don't think I would give this up for anything in the world.