USUALLY, all mothers want is the best for their child. You have put a lot of effort and sacrifice into losing weight, maybe your mum wants you to be careful.
If you want avoid gaining weight again then you NEED to educate yourself. Be able to say "we actually mum, this food is fine to eat".
You were right with the calorie counting: weight change is fully determined by how many calories you eat
Find your maintainance calories then...
To lose weight, eat under your maintenance calories.
To maintain weight, eat at your maintenance calories.
To gain weight, eat above your maintenance calories.
Keep in mind that if you also want to be healthy, you should be eating healthily.
Weight change is not correlated to your health, but it can help it.
You gave a good example. You were starving yourself to lose weight. Unhealthy, don't do that.
I wish you luck in your journey!