Drastic is not the word I would use to describe it. You need to stop that shit and simply eat more sensibly. It's not a race.
I agree with this man. I've been on the far end of what you're doing. Maybe even worse when I was doing a deficit, working out, and not drinking water. For a month I even did one of those "cleansing" diets which was just lemon juice and no actual protein while still working out. I kept doing these bad things to myself for a year.
I was tired, hungry, and weak. I was completely anorexic. I totally obsessed over the number on the scale.
Thing was, I know how to eat right, how much to eat. I knew what I was doing was bad. A single thought kept repeating through my head "No normal person does this". But I ignored it.
Don't let it get anywhere near that. So I'm not here to argue or judge. Just like the other Gaffers, I'm trying to look out for another. In addition to going to the Doctor, and a Nutritionist, and a Psychiatrist. I saw this thread and these guys have actually been the most helpful. Maybe I can pass along some knowledge.
You're going to be burning a lot of muscle with that much of a deficit. Take into consideration:
A gram of protein has 4 calories, a gram of fat has 9, a gram of carbs has 4.
Even if you're eating pure protein, you'd need 150g/600cal worth just to maintain a lean mass of 150lbs WITHOUT exercise. Also consider that your body needs fat and carbs for energy. It doesn't sound like you're getting much protein at all.
Looks like the reason you're ok on the energy is that you're eating carbs. Things like the fiber bars will last you a bit till you get hungry again.
My advise, for anyone thinking about doing stuff as drastic as I did is that if you have to be that strict. Do it right. Get your body fat tested as accurately as possible (in my case I did hydrostatic), figuring out exactly what your maintenance requirements are (including activity level), and follow a cut (or in my case bulk) routine of eating +- 10%-20%