Vaccination Hesitation...?

I am the mother of a 4 month old and a 2 year old. My 2 year old has received all of his vaccinations with no issue, and I assumed that my baby would as well. However, a couple of hours after her 2 month vaccines, she began screaming hysterically. It scared me, really, because I had never heard her scream like that. It lasted a couple of hours, and while I wanted to call the Dr. back, he said not to worry unless she cried more than 3 hours. The crying was awful though, she wouldn't nurse, wouldn't be comforted, it was very traumatic. She hasn't been like that since. Now she's 4 months and it's time for her next round of shots, and I'm so nervous. Our doc is very pro-vaccine, and I'm not sure how to talk to him about possibly delaying her shots. When I brought up concerns with my son, he was like, "Why WOULDN'T you vaccinate?", as though it was nonsense to even consider not. I've been doing a lot of reading, and everything is so confusing. How do I go about talking with our doctor about delaying vaccines? Is that sort of crying normal? I've read some things that point towards the pertussis vaccine being a probably cause. Also, I want to go in for her 4 month well-baby, but don't want to deal with the vaccine issue until I know what to do!! Help!