I'm pretty sure that most mommies feel like that.
Here's my story and suggestions... My situation (which is actually "worse" than most...): We have four kids... 6, 4, 2, and 1. My husband works seven days a week- no sick days and no vacation. I work four days a week. I work when he doesn't work. We play tag team- as soon as I'm off of work and come home, he leaves for work. The days that I don't work my husband is gone ALL day. We have SO little extra time.
I actually scheduled my extra time as "M. chore time" everyday. I have found things go better for me when each time of the day has it's designation (with plenty of "free-time" slots too!). I do all these things after the kids have gone to bed. My husband comes home around 10 pm, so I wanna be awake anyway to spend time with him, and hopefully I'm done with the chores. My husband also does a TON of housework, too. We both are very fair to each other about it (even though he works way more), so whenever we get a chance DURING THE DAY, we seize it, and clean-up or whatever needs to be done.
Some ways that I do things during the day are to do it when the kids are feeding themselves (yes, even the one year-old), when they are playing in their playroom with the baby-gate at the door way, when they nap (sometimes my two year-old doesn't nap...), and I also have them "help"... I give them busy stuff to do that either could actually help me or stuff to make them think they are helping... and yes, I'm referring to my one year-old as well.
It is frustrating though, when you don't have the house the way you want it. I understand. You could ALWAYS get a babysitter or switch baby-sitting with another mom. There are also places that you can drop the kiddies off for "date night" or "M. time". ...I have NEVER gotten a babysitter so I could do chores, though! there's nothing wrong with it, though. BUT You should try to not focus on what you need to get done, but what you have already done. I strongly suggest a schedule, too. I feel way more organized and accomplished with one.
Oh, and I don't know how those awesome moms that have husbands who are away on business all the time or in the military away in some other country deal with things!!!! I can't IMAGINE it, but I have plenty of friends in that situation and they deal with it! Not to mention the strong single moms, too!!! (and MANY other situations...) So, maybe thinking about other situations that may be tougher would help you appreciate the situation you are in now, in turn helping your perspective. It always helps me. I think- if they can handle THAT I can handle THIS:)
Admittedly, I don't get any time to myself where I am not doing housework or some kind of work, I take NO longer than 10 min in the shower, I NEVER get myself done-up or "pretty", my husband and I hardly ever go out at all, I find relaxing a VERY hard thing to do, we don't go on vacation, BUT I know it won't be like this forever:)
Hope this helps!