Reading between the lines could it be that you're a sort of an up and down type of person? Thin one year, overweight the next? Sometimes it's good to have a close friend or family member give you advice and opinion you can trust but generally I would stick to what you feel most comfortable at weight-wise. If you're fit and well and strong and not losing breath and struggling and feeling down then stay at the optimum weight you're happiest with.
And eat foods with good fats and lighter protein, lean meats for example, plus all the veggies for nutrients.
I think it's great that you're walking because this is one of the best exercises you can do to maintain health and a stable weight. Just make sure you vary the walks so that your body is challenged regularly. Go a bit further one day, choose a slope to walk up and down, keep your joints oiled!
I hope you get a balance you feel is right for you!!