It sounds like your son is not liking the real world and/or your milk supply may need a boost. If it's milk supply, The Nursing Mother Companion and/or lactation consultant would be in order. You can try giving him goat's milk when he is fussy to see if he is still hungry. If he guzzles down an ounce, then you know you need help with milk supply. If he's not hungry, then the book will help you figure out foods that might be upsetting him. I know with my daughter I thought she was sensitive and was very careful with what I ate. When my son was fussy, he was still hungry- period. He even had a yeast rash and didn't care as long as he was fed. (I had to eliminate sugar and processed grains, etc. to clear up his yeast rash since he was exclusively breast fed at the time.)
Do you have a sling? If it is reflux, keeping him upright will be more comfortable. But you said he's not happy in a bouncer so he may just want to be close to you. He has been snuggled, fed and warm for 9 months in your womb and now he doesn't have that. ("The Happiest Baby on the Block" explains this well.)
If your worried about looks: I didn't want to look hippie with my daughter, but I had to consider slings when my son came along since I new it would make us mobile at the playground. I never knew it was so easy and had such benefits- calm, content, secure baby. If you are going back to work, you will probably want to sling him up after work so he gets his snuggle needs met. If your babysitter is willing, she can sling him up, too.
My first was a girl and second a boy. My son has been much needier than my daughter. I used to put him in the sling a lot when he was smaller, now I use it when we are out or if he is super fussy. (Since he can sit up, I can put him on my back and cook dinner while he is getting his need met. I have a Baby Bjorn type carrier and it was too hard to put him on my back. There was no way I was going to cook dinner with a crying baby at my feet or in front where he can get cut or burned)
If you have never used one, please go to Peppermint in Richardson (www.peppermint.com). They will show you how to use a sling and probably recommend a ring sling. It is adjustable and can grow with your baby from newborn to 35 pounds. They also have classes and live web help if you can't get to the store. I admit I couldn't quit get my sling right with the directions that came with my sling, but the class cleared that up within 5 minutes.
I got a second sling on eBay dirt cheap so now one is clean and packed in the diaper bag whenever we go out. When you get good, you might see other moms hauling out the stroller and everything while you are walking away with your baby in the sling.
Oh, yeah- added bonus of the sling, people will admire your baby without touching and kissing him. Since he's in the sling, they would have to invade your personal space to touch him. So you can be mobile with him and your daughter much sooner while still giving him some immune protection.
Sorry for the ramble, but your bio says you are dealing with a lot of this without your husband. I just wanted you to have lots of ideas to check out/eliminate since you are probably tired right now. I wish you lived closer. I have a just-turned 7 year old and 10 month old, so feel free to email me.