Anorexia coming back?

I dealt with anorexia in my teens. I'm now 37. I lost a lot of weight after having my last baby due to extreme stress, anxiety, and depression. I thought at first it was because I am breastfeeding but the weight continued to drop. Now I think it has manifested back into an eating disorder. I like the way I feel skinny. I hate fat rolls on my body and have always had an issue with feeling fat and looking fat. I have 4 kids and I will not allow myself to stay fat after having them. My son will be 2 this month and still nurses. I'm 20 pounds below my pre-pregnancy weight, which was already considered below average, and I struggle with wanting to gain weight so I can feel healthy again and wanting to stay skinny so I can not be fat. I feel like the skinnier I get, the fatter I look.