You stopped taking a supplement, but are you compensating that with more food? I think that is your problem. Supplements are merely to help you fill in your daily needs if you find it difficult to do so with your daily diet. If you're off it, you need to compensate with regular food. You're problem is simple, you're not consuming enough calories. It matters very little if your're a vegetarian or not. Vegetables do have protein, which may not be as effective, but they do build muscle. You just need to be smart when eating them.

There are vegetarian body builders out there, and although they won't get as big as meat eaters, they do get impressive physique and can get pretty big. You may want to consider including eggs and milk into your diet, if it doesn't conflict with your beliefs or anything.

Oh and although I'm not a vegetarian, we're on the same boat when it comes to weight loss. I can lose about 1 kg a week if I don't eat enough consistently. That has happened a few times, and has happened about 2 weeks ago when I had a fever and had little appetite for a week+. Even with all that water weight the scale showed that at the end of the week I lost about a kilo.

Stay positive, you can do it. 

you should have no issue putting on weight as you can indulge in healthy oils from nuts. believe you are allowed milk so go for whole milk or chocolate milk if you aren't lactose intolerant. if you are, you could try almond milk if it's available in malaysia.

don't forget to eat peanut butter too. some vegetarians eat eggs so, this could also be a viable source for your protein and some good cholesterol.

i would skip the milk powder and go for actual liquid milk but since you don't drink milk then you'll need to look at other options.

good thing you are able to eat cheese. go crazy with it and i would suggest making some egg and vegetable pizzas to bring along with you. eggs i'd go for 4 whole eggs a day but that's just me. egg whites on the other hand are free to consume.

as you're worried with budget, your best bet would be to keep calories up and the only thing that is effective in doing so are fats. it goes without saying that you should be selecting the healthier fats to add into your food. which is why nuts such as almonds are really 'economical' in a sense since 1 cup of almonds can give you 800kcal and 30g protein right there. i'm guessing this would be about RM4-6. not bad for a meal if you ask me.

took 8 month, from 56kg to 71kg

a bit slow,ok lah as long gaining...

target 75kg b3 march 2013...

You need to stop comparing like that. You need to break down how many calories and nutrients you get for every Ringgit rather than how many grams of bulky powder in comparison.

A liter of milk costing less than RM5 has around 800 calories (a third of what you need it looks like) and provides 40-50g protein (check the labels). If your powder can provide at least 260-325g protein for the powder then its about the same. But if the whole pack provides less than that, you are paying for less calories and protein. Get it?

Nuts are great sources of nutrients, proteins & fats. Get them raw if possible. If you cant, then read the labels and ingredients to make sure you aren't eating extra sugar or additives. Almonds are touted as best. But pistachios, walnuts, pecans are all good too so feel free to mix it up so you don't get bored.

Also consider that there are vegetables that are high in protein. Beans are top of the list. Then peas (which can be argued to be beans as well). Not to mention, they provide lots of fiber so your BM's will be nice and regular So look at baked beans, chick peas, black eyed peas, green peas (I like the frozen watties brand-delicious and sweet), split peas, red lentils, etc.

Google will provide many sources for you to find protein dense vegetables.

For eggs, it depends. I aim to eat about 5 eggs a day. That helps me reach my fats for the day, provides me with roughly 30g protein, 380-400 calories and it costs less than RM2. Not to mention it is quick, easy and versatile.

So if you can stomach it, you can always eat like 10 eggs and a liter of milk for less than RM10 a day to get around 100g of protein and around 1500-1600 calories. Not bad right?

Unfortunately, you are going to have to find a way to budget for food. How little protein you can get away with is up for debate but I suggest aiming for at least 100g a day then use the remaining calories (and money) to be filled up with cheaper foods like rice/bread/etc.

Good luck figuring it out.