VOC with children

So a few of us Mom's from school have given ourselves this special name,like a sorority of sorts. We are God blessed with our special angel children (read sarcasm), so we are allowed to do such things. And today was our first outing with our children included.
We went to Weston's Red Barn Farm. It was gorgeous and the animals smelled ripe and ready for petting. So we did just that, along with four other bus loads of children from various schools. Yikes. I thought I would be cleaver and dress Bella, Remi and myself all in red(it also is red friday)so we would be easy to spot, but one of the four groups had also choose red today for their color, along with groups of blue, orange and yellow. Oh how Remi wanted to be with the yellow group.

I was a little hesitant for this trip anyway due to Bella and outings, but I figured we would all be dealing with the same kind of issues. Ha I was quickly proven wrong. Bella didn't want to be at the farm the first second we got there. Rolling on the ground, kicking and screaming and often found sitting alone in the dirt somewhere. The hayride was the only calming factor for Bella that seemed to regroup her senses. This hayride took place at the end of the excursion, minus all but one of the other families. How was I to know that the others hadn't purchased hayride tickets? The lady at the gate told me my group had purchased these tickets. Really?

When we were done with the ride we had lost the group, which we found out later, had left us to go to the next place, lunch. Um, okay, thanks for the heads up. Glad we didn't spend 10 hellish minutes looking for you, before dragging the kids back to the car so I could use my cell phone.

So I packed the whining, hungry, thirsty children into the van and drove the five miles down the road to get to the cafe we had all planned to meet at.

Lunch was worse. Bella refuses to sit in her seat, rolling on the floor, licking the air vents on the floor, smashing her food, screaming when told to sit and using the bathroom as many times as I would allow her. *I would love to blame this on the pure exhaustion from the farm, but this is typical Bella behavior at a restaurant.*

Please someone tell me what I am doing wrong? Please someone help me understand and deal appropriately with Sensory Intergration Disorder? Please someone tell me it will only get better and Bella will be able to handle daily life one day without trained professionals following her every move?
Please tell me I am not selfish for wanting the VOC to never again include our children in our outings?
Please tell me I wasn't a bitch when one of the other Mom's said, "this was fun!" and I didn't reply?