mother-daughter crisis

Lately I feel like 90% of my relationship with Olive has a sour taste to it. There is a lot of crying and frustration that goes on in our days. On everyone's part; Olive, Emy and me as well.
Its very difficult to explain. Mainly because it is very painful. Olive IS so wonderful to me. I could write a hundred things I love about her easily, and we WERE really really close. I had a very deep bond with her before I got pregnant with Ema, and slowly I have felt that bond erode. Even with all my effort to keep it intact. I feel like I am failing her.
We are both unbearably stubborn sometimes. Of course I am louder, I am stronger, I am bigger, my mind holds the knowledge of past, present, future, and so I can endure. Except this is not a virtue of mine. I do not want to parent by her by force. When the day begins with crying, and everything that Emy does is an offence that invokes shrill screaming on Olives part, and only after imploring for some kind of explanation for the howls does she whimper; "she's touching my table" "she's coming to get me" "that's my toy" "I want yoghurt too"  . The day ends with crying too. I feel like we've been fighting all day, and I am stretched thin. And I dont want to see her any more. I am relieved when Greg comes to pick her up. Obviously these feelings make me feel guilty as well.

The most obvious explanation is a sibling rivalry. I spend time with Ema at night that I dont get with Olive ever any more. Emy is still really quite helpless and in most conflicts I feel obliged to come to her aid. She cannot stand up for herself after all. Especially because it doesn't matter which toy Emy is playing with, they all belong to Olive in Olive's mind. Even if they dont she "just wants to see it for a minute mommy". When there is no conflict with Ema going on Olive spends a lot of time hanging off my body. From my neck, my legs, leaning on me. It is not pleasant physical contact. I make the effort to grab her into a cuddly position, but she still tries to make it unpleasant. I can see that she wants ME, she wants my attention/approval/love. I do not blame her, and I think she deserves exactly what she wants. But it is not possible for me to give it to her. Because what she wants is to not have to share me.
Most of my friends who have kids of similar ages have not had a second child yet. I see them with their little ones running around with joy and excitement, most importantly assurance. I see the connection that I miss having with Olive. I feel sad. And I dont have anyone to swap experience and frustration with. I dont know anyone with answers or wisdom to share. I feel very alone in this. I am not sure what to do.
I am trying to be patient, and build new connections. I have decided that I need to start setting aside time for Olive to spend with me all alone. Logistically its tricky, but I am hoping even a little one on one will help us. When we are frustrated with each other, I try and make us space, one of us upstairs, one of us down. Or I sit by myself (with Emy) in the bathroom. I call Greg. Olive likes to go lay down when she is upset. I ask her to blow out air when she's really lost her cool, and I ask her to help me blow out air when I have lost my cool. We do a lot of apologizing and a lot of forgiving throughout our days. When I need a silver lining I think to myself that at least we are learning that everyone has lots and lots of feelings, and those feelings aren't too much to handle as we get through them one by one. Oh boy do we ever.