I, too, know exactly what you mean! There is LOVE abound at our house, AND there is the underlying "this isn't what I signed up for" in my heart. I wouldn't worry so much about the resentment, it is a completely human reaction ... I would, however, avoid guilt over feeling the resentment ~ it just compounds the problem. Acknowledge the pissiness and go on with your day, the only thing you can change is your perspective.
Now for practical help: do you wear your baby during the day? I found the "kangaroo" position in the sling allowed the baby to get stimulation from the environment instead of only me, and the closeness gave the baby confidence to interact with others. Are you co-sleeping? Have you mastered sleeping while nursing? Nothing like prolactin to induce a cat nap (OH, I miss it!!!). Oh, notice that, too ... when I would get down about life and I had a baby (or toddler) to nurse, I would sit and visualize the Prolactin doing it's job of keeping me calm and sane, insuring I'm the best mom I can be (even if all I have to offer at the moment is my milk!). Acknowledge the things you're doing right
during the day (at the end of my day, if both kids are still breathing, it's been a successful day!!), even if they seem trite (woo hoo, got that diaper changed ~ go mom!).
And if you want a remedy for those moments, might I recommend Bach's Rescue Remedy. It is an amazing help to me .. I also use the Cherry Plum essence, it's for the moments when I feel like I really am losing my mind... you can find these at most healthfood stores (unless you live near me-I drive across the state to get mine). There is a remedy for almost anything, you'll see when you start researching ... just prioritize your "complaints" and see what fits.
Re: the baby looking like dad
Very funny! Dh's parents divorced when he was three and he didn't see dad for almost 27 yrs. The first time I saw his dad's picture, I almost fainted ~ It was exactly Mitch's face, but white!! (Dad's german and Mom's mexican) I finally asked MIL how did she do it? Looking into the face of her ex EVERY SINGLE DAY??? She admitted she had to really catch herself to react only to MITCH and not to the Father he looks like! I met FIL 4 years ago, it was strange to see what my dh would have looked like had he been able to live into his 60s. (both dh and fil died in 2000) My Hannah looks like Mitch, but I've always said "daddy on the outside and mommy on the inside" ... this has come to haunt me, as Hayden favors my side in looks and daddy's side in personality... tee hee
Blessings to you and yours