Like all cheeses, Mozzarella is quite fattening but the calorific content can vary from brands. If the Mozzarella and tomato salad had olive oil drizzled on top then that would be quite fatty too - remember Olive Oil is 'good' fat.
The half portion of pasta will depend on the sauce you had with it.
You can eat pretty much what you like, as long as you do plenty of excerise and eat a varied balanced diet.
Sorry to sound like those diet magasines, but I lost 4 stone in 6 months by doing the above...
Best wishes,
Mowbray