Exhaustion

It's 11:00 and Helena has been crying for an hour and 52 minutes. She went down at 8:00--like always--and woke up around 9:00--like always.
This has been going on ever since I got back from Tennessee. It's exhausting. It's frustrating. It's discouraging.
I spend all day long with both girls, mostly at the house or within a 1-mile radius of it, and by the time Jason gets home, I am eager to spend some time with him. I work all day long to make sure that Helena eats and naps on a good schedule, in hopes that keeping a routine will help her sleep better at night.
But every night the same thing happens.
I don't know what to do about it. My gut says to let her cry it out! But we are all sharing a room right now, and so if we let her cry, it wakes Tempe. Plus, Helena doesn't "cry it out". She gets more and more worked up until she is screaming bloody murder.
So, we rock, and we pat, and we walk, and I try to nurse, and some nights it works, and some nights it doesn't. I try to remind myself that she is just a baby and she can't tell me what she needs. I try to remind myself that this too shall pass, it's a part of life, I'll miss it when she is grown, I'm lucky to have her even if she is crying, etc, etc.
But all I really want is a few hours of peace with both of my kids asleep.