How can i gain lean healthy weight? help!?

I had a baby 6 months ago and sarted dieting\exercising to lose baby weight. I was eating healthy and enough calories to lose a healthy 1-2 lbs per week. In april, I decided to go vegan at a healthy 109 lbs. I lost 10 lbsin the last month, including 3 lbs just last week. ( I ran really hard at the gym). The problem is that I've become very paranoid of gaining weight that I have a hard time eating more than 1300 calories when I exercise. I realize I've developed a compulsion, and do NOT. Want to lose anymore weight. (I'm 98 1/2 lbs now) I feel tired, weak, and can still run, but my legs feel awfully tiredafterwards. My question how can I safely gaim weight? Should I eat more protein? Lift more weifghts and do less cardio? I am a mom and need energy again!