Post Pregnancy Weight Gain

My weight pre-pregnancy was 58kg (127 pounds). During pregnancy I didn’t gain much weight and didn’t weigh myself only when the hospital weighed me. When I had my son last July he weighed 7 pounds and 12 ounces. The weight fell off me. However, after disturbed sleep, breastfeeding, less exercise initially and over consumption of sugar I gained weight. I started this plan on Tuesday (1 June was my birthday) and I weighed 68.9kg and today I weigh 65.8kg. My goal is to get back to 58-60kg before we have treatment for baby number two in July. I haven’t experienced weight issues before and was naturally slim pre baby and I never weighed myself as it wasn’t an issue. I am eating between 12-7pm, two meals, no snacks and no sugar or flour (I am sober so no alcohol either). I was eating way too much chocolate and sugar before. So my question is in two parts – a) I know on this plan I will lose the weight easily- what happens when I reach my goal weight, how do I adjust my protocol so that I don’t keep losing weight? What do you recommend increasing? I will probably introduce an exception meal at the weekends at that stage (I know when I eat zero sugar I can go very thin) but I am committed to not eating sugar and maybe I will add in a bit of pasta or bread but those are not triggers for me.

b) Is it ok to keep with two meals a day and intermittent fasting when pregnant? I think it should be ok as I was never much of a breakfast person but I also know from last time that there were times where I wanted to eat and times I didn’t which wouldn’t necessarily fit within a plan. I am thinking when pregnant that I will eat when I am physically hungry but keep with no sugar and minimum flour.