It will be short lived! :) Breathe! My son was 2.5 when my daughter was born and he went through a very "two" phase, just trying lots of stuff to get attention. We picked our battles. He needed time to process and adjust. I also found that once my husband went back to work, things settled down. Having daddy home is great, but that is just one more thing to adjust to, one more thing that is different, in addition to the new baby. Definitely have dad take care of baby, too, so you can be with your older daughter and she can have some special mommy time. The first week, I was with the baby more, but then the next week, dad was with the baby more so my son could adjust back to having me around to play with. This worked out great.
I wore my baby in my K'tan carrier and she slept in that thing while we'd play and take walks and go to the park and even eat lunch. This was my son could have mommy time, too, and my hands were free to play! My son helped get diapers for her, he'd get her special toy that he found for her before she was born, he picked out outfits for her to wear, and so on. Their bond is so special and sweet now. You'll get there, too! Give it time!