We got back on Sunday and we had no problem. We had the following...
2 large suitcases
2 small suitcases (to keep the large suitcases below 50#)
1 set golf clubs
4 carry on bags
3 year old
16 month old
double stroller
We didn't have a car seat, but I have flown with one in the past and I second the recommendation of getting a rolling bag with backpack straps to get it through the airport. They are lifesavers. I found mine at babies r us for about $20.
Before we left the house I made sure that DH could handle all four checked bags by himself. I stowed/hung the carry-ons on the stroller and pulled the golf bag.
The hardest part was getting on the shuttle from long term parking. We asked the driver to stop at the curb check for Southwest and he was happy to help us pull the luggage off and set it in front of the podium, we were also happy to tip him.

Honestly curb check saved us a LOT of trouble. Then it was just juggling shoes, carry-on bags, kids and stroller through security. I took DS's shoes off in line and stowed them in my carry-on, stuffed jackets in the bags just before they were checked at the curb and we juggled the rest. It was easier than I thought it would be.
I know it is hard to but don't worry, you will make it through with flying colors. Remember don't let anyone rush you. They can wait a couple extra minutes.
Have fun!!!
I almost forgot. We also practiced waling through security with DD at home. We made her take off her shoes, walk through a doorway and wait for me on the other side. We would mix it up with beeping and wanding. She loved it and was great when we went though security. She was actually upset that she didn't beep. I don't know how much that helped but I think it helped her feel more confident.