Breastfeeding/formula decision

So while I am here still pregnant at 38 weeks, i am been having a back and forth decision on breastfeeding and using formula. My second child, I breastfed for 3 months and it was not a pleasant experience. I felt depressed and I dreaded feeding my son. He want s to feed, it seemed like ever hour and a half. So with my third I decided to go to formula so I can enjoy being a mother and not feel so depressed with exhaustion and feeling alone. I posted about it before and had so many positive words while I felt guilty about my decision. Now that I am coming close, I almost want to breastfeed and try to pump most of the time while substituting and also use formula. I just want him to have the nutrients and benefits of having breast milk. My first son was not breast fed and when he is sick, boy is he sick but my second does not get as sick and sometimes I feel it is because he was breastfed. If I decide to give him breast milk it may only be for a few weeks. Have any moms gone through this also and worked out better for them? I just want to be a happy mom and enjoy my kids.