Re: use of "a pizza" and "pizzas".
And use no article and the singular if you just mean to food as a concept.
A: Do you like pizza? (the food itself)
B: Oh, yes, I love pizza!
A: Maybe we could get a pizza for dinner tonight. (We only need one pizza.)
B: Sounds good. Let's get it from Romeo's. I had one of their pizzas (they make many types) last week and it was great - it was their taco pizza.
A: Taco? That sounds weird!
B: Trust me, it was a great pizza!
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.