Jump as soon as you can!
An example plan, not so far from yours, could be
Breakfast - Porridge made with milk, instead of water, topped by some nuts and honey, if you like it. Hot chocolate, banana, more than 1/4 blueberries... as much as you want.
Snack 1 - Try to have a mid morning snack, some fruit salad, for example, with caloric dense fruit, but still fresh and not heavy - mangoes, grapefruit, banana...
Lunch - Good to go for protein, as you don't eat meat, but you can really have 1 whole egg everyday without any unhealthy outcome, so I would say : carrots, if you like them that much, but I'd have carrots, tomato, white beans, onion salad, with some olive oil, with an omelet with one whole egg and as many egg whites as you want. Pineapple, or go for something other than fruit for dessert once a day... It can still be nutrient dense and healthy: ricotta with homemade pumpkin jam and walnuts is a favorite!
Snack 2 is okay, greek yogurt and fruit :D
Dinner - For protein, no need to throw away any more egg yolks per day. Why wouldn't you go for tofu, soy chunks, tempeh, even lentils? Those are better for creativity than egg whites. Tofu curry, brown rice with raisins, a good salad or steamed veggies = Happy forever! I think you should have this rice, or pasta, or potatoes in one of your daily meals. And greek yogurt, as it's never too much.
Keep that last snack, just allow yourself an apple if the mini apple is not available at the moment!
This would add calories to your plan, without adding processed foods, if you're not willing to have them, and without making you stuffed.
For an inaccurate and quick review of those extras: milk ~100, nuts and honey ~100, snack 1 ~200, whole egg and olive oil ~150, egg whites for tofu ~100, rice ~200, raisins ~50
This would add around 900 calories to your plan, 1000/1100 if you go for the dessert idea, without that much of a change, avoiding stuffing you or getting you high on pizza hut, if you don't feel you want it, or crave it, or miss it, of course. So, from 1000 to 2000, not so hard.
ahah is this for real?
sorry when your smaller a normal bmi looks odd on short people
No, the BMI works through direct proportionality.
If you're talking about having a small frame or structure, the weight gain will not know the difference, I guess. It will happen, with either a small or big structure, until your body is comfortable and feels healthy, but you can't gain weight forever, it's not possible. There's no way to know where in the BMI your body feels comfortable prior to gaining weight... Only that will make you know for sure, as your body will respond.
The BMI uses your height and weight, but it means zero as far as the way a body looks is concerned. We can be both 5'3, 120pounds, same exact bone structure, and still, completely different bodies.
Think about gaining the weight you need, and when you're healthy you can make your body look as good as you want through working out, gaining lean mass and staying free from restrictive eating habits.
There's no way to say I much you'll gain, but you won't almost fore sure gain to more than your pre ed weight, if you go for a full recovery. Think about how you didn't feel bad with it at some point in your life, and think that maybe back then you didn't even know you could make it look better without having to eat close to nothing and kill yourself with aerobics... now you do. It's worth it!