congrats on your new bundle of joy
the general rule is 9 months to put on, 9 months to come off. So give yourself about a year. Really!
Part of packing on the weight while pregnant is to ensure you have enough fat resources to provide the amount of breastmilk your infant needs.
You may have come here looking for more ways to whittle calories or increase your exercise regimen, but I dont think you should do either of those right now. I don't think you should be dieting/restricting calories. You will
slowly lose weight without dieting from the BFing. You're suppose to get like 250 EXTRA calories a day when breastfeeding. Your body burns something like 300-500 calories just by breastfeeding. The weight will come off in time.
Focus on eating healthy, nutritious complete meals. Any mom of a newborn feels exhausted at the end of the day (beginning of the day, midday, all day

). You probably need around 2000 calories a day to sustain you, breastfeed the newborn, and keep up with your 19 month old.
Since this is your second time around with a new baby, I don't have to tell you that this time period can be very stressful. You shared that you have been anorexic before. When life is so chaotic/demanding it can be easy to turn to old forms of control (i.e. eating disorder). Please talk to your partner, a family member, or friend if you find old behaviors creeping back.
Best of luck to you and your growing family! Oh, to have a little little baby again. Mine turns 3 on Saturday