Hi Teri - I really feel for you!! That must have been awful and I know how hard it also is to try and drive (or do anything) with a screaming baby. I agree with the suggestions you've already been given. Babies need to suck and some babies more than others. If he won't take a paci - work on the thumb. As for the nursing to sleep, my dd did that for ages, and we gradually were able to get her off it. As she was nursing to sleep, I'd use my finger to break the latch before she was asleep. I'd rock her, pat, shh - whatever, to try and get her to sleep. If she'd cry or start to fuss at all, I'd re-latch her, wait a few moment, and try again. She'd eventually let me take her off and finish falling to sleep another way. Then I was able to gradually start putting her down more and more awake. Took a long time (months), but it did get better, and now she goes to sleep from awake most of the time.
I, like Stacy, also wore my baby around almost all the time. We went shopping and I'd have her in the Baby Bjorn - until maybe a month ago and she's 14 months! She'd cry in the stroller. At 4 months, I still faced her in most of the time so she'd have her face to my chest and slept better that way when out. I tried to time outings for as soon as she woke up, or when I knew it was ok if she had a short nap.
Keep us posted, and let us know if we can help you more! Hugs!!