Hi S.,
First let me say that being frustrated with your child's sleep patterns is a normal part of being a mom, and I understand the frustration. When it all works well, it is great, but if anything is not working as it should, it is hard to know what to do to fix it.
My suggestion to you would be to try to put bedtime earlier. A book that has helped me with sleep patterns is "Healthy Sleep Habits, Happy Child." You are right in assuming he is not getting enough rest, the waking during the night is another sign of that. Oddly, children sleep worse the more overtired they are. So, by putting his bedtime earlier, you may find he will stop waking during the night. Also, if he is getting used to that attention in the middle of the night you may need to minimize the attention you give him when he does wake up. But I would try adjusting the bedtime first.
I also wonder if he still needs a morning nap? My son is 15 months old. Here is his sleep schedule: Go to bed at 6:30, sleeps usually all through the night and wakes about 7:30. (If he does wake during the night, I wait awhile before going in to check on him, sometimes it is just a couple cries and he'll go back to sleep on his own). He takes a morning nap about 10:00. I can tell he is growing out of this as some days he won't actually sleep, other days he'll sleep two hours. Then he takes an afternoon nap around 2:00 and usually sleeps about 2 hours.
Your schedule definitely doesn't have to look like mine, especially if you want to fit mother's day out in there (my son goes without morning nap about twice a week for activities like that and church), but I would suggest you read the book I mentioned as it might help you find some creative sleep solutions. Good luck.