Weight loss advice

Would any of you kind ladies be willing to offer me some advice? My baby is 11 weeks old and I’m really desperate to loose this weight. I need to loose 67lbs in total. I’m wanting to do it the healthy way of loosing 1-2lbs a week. Thing I’m struggling with is knowing what calories I should be consuming. I’m concerned that with the calories I’m burning a day just from walking the school run (roughly 3 miles) I’m not consuming enough. I have to tread carefully due to an eating disorder, I’ve not had an episode in 2 years so I don’t want to lead back into that. Im eating below 1350 but burning averagely 700.