Dude you eat twice a day. Your stomach is probably the size of a tennis ball at the moment. You have to figure out a way to get more meals into your diet. I've been in your shoes and the less I ate the less my desire to eat was. It's just that your stomach shrinks and can't take the same amount of food. Usually, when I didn't have time to eat (dumb me ... I now know this is bullshit. You can ALWAYS figure out a time to eat) I was having about 1 big meal a day (same as you: a big ass dinner that includes whatever was in my fridge). I then started having more food by adding one extra meal every few days and my appetite gradually came back. Start having lunch and you will see you'll get back on track
If not ... then go see a doctor to make sure there's nothing wrong. If that will make you feel calmer, I managed to lose about 10-15 lbs in 4 weeks by switching from 6-7 meals a day to 2-3 meals a day. So yeah ... if you don't eat you get skinny.