So I've been really stressed out the past 10 days because of a review meeting with my boss and I've been working long hours to get ready for it.
Usually stress drives me to eat mindlessly but this time around, I just haven't been eating!

Now that the meeting's done, I've been looking back at how many calories I've been eating and it's pitifully low (400-700/day)! What have I done to my metabolism? I'm not even getting proper hunger cues anymore!

Should I just start eating 1200 calories again? Has my metabolism slowed so much that I will gain weight?

I am not sure but I don't think 10 days is enough to change your metabolism. Maybe add 100 cals/day? Smarter people will be along shortly.

Nah, it won't hurt. I would worry if you were doing it at least 6 months or something like that. For now, try eating high-calorie type of stuff like nut butters, nuts, avocados, a bit more meat and maybe some full-fat stuff, that way you don't have to stuff yourself and still get all of your calories in. I'm sure it will pass and you will get your hunger back.

PS- Oh, you may or may not notice an increase on the scale but please don't worry. It will pass after you start eating your usual calorie intake, just something about water retention and stuff like that, lol.