Congratulations on wanting to be healthier & lose a little weight in the process.
Even if you have pizza... there's no reason to say "The HECK with this." A person I admire on these boards has a saying. Let's say you're climbing up some stairs. You happen to slip a little on one of the stairs... do you then turn around and toss yourself down the rest of them simply because of one slip? It's silly and pointless to give up when going forward is what we really want to do.
We're human. We all slip up. The point is that if you stick around here you'll find a priceless resource of all the humans here that keep going regardless of how many slip ups happen.
Find a plan that fits your life. Work the plan. When you do slip-up, get immediately back to your new routine.
Best of success!