calories too low but eating 3 meals a day?

I've been reading peoples posts about how they aren't eating enough calories per day and it got me thinking about my own so I started looking at my own eating habits and an average day would be as follows:

• Breakfast- cornflakes with raspberries and a tsp honey (180 kcal) and a cup of tea (20 kcal)

• Lunch- Half a pitta with lettuce and flavoured chicken (120kcal) with a tangerine (50kcal)and a yoghurt (50kcal from weightwatchers)

• Snack- something like a little bag of party rings (90 kcal) and a cup of tea (20kcal)

• Dinner- Courgetti and quorn meatballs with chopped tomatoes (around 200 kcal) with fruit for dessert, often pineapple (74kcal)

That all totals up to around 800 calories a day which seems very low but I'm eating three meals and snacks. I don't feel hungry and whilst my weight is dropping it's at a steady rate (I've lost 6 lbs in 10 weeks). My biggest worry with weight loss is that I'll get carried away or mess up my metabolism or just put it back on later in life.

Do I need to eat more?