Morning Dianne! I am going to preface this with saying it is just general advice and obvously not making any consideration for other medical conditions you may have (high cholesterol etc). I think it is generally recommended that you make the calories you eat worth it. So use full fat dairy and try to add some to your current meals - so maybe omelette with cheese, hot chocolate/smoothie/milkshake with icecream, add cream to soups etc. Also try some high energy snacks and plan them frequently. So some nut/dried fruit packs, cheese and bikkies, avocado on toast and/or glass of milk. Definitely try to schedule in your meals/snacks so you eat regularly and get in the swing of doing so. It sounds silly but it can be really hard to regain your appetite if you have lost it - some times this happens when you get stressed/busy. The key is to make sure you can increase your calories from nutrient rich food too not just empty calories as you will also feel better rather than if you ate 'junk' food. You could always get some Sustagen if you were finding that this isn't easy - also it may take a little while for your body to adapt to putting on weight. Did the Dr offer a dietiation/nutritionist for you?
HTH - good luck as it is hard work and people often don't realise how hard it can be. xxx