It's a good decision by you to want your baby to breastfeed exclusively. Stay in this positive mood. The more baby suckles at breast and the more emptier breasts get, milk production boosts up accordingly. Hence try to feed baby every 1.5-2 hrs and post feed, empty the breast by hand expressing and you can feed that remaining milk to baby by spoon. Even night time feeding is important to maintain the milk production cycle. Always offer breast first and then the formula milk. And don't think that you are producing only 20-30 ml. It's different when you express the milk and when baby feeds directly from the breast (it might be more). Maintain a balanced diet. Some common foods from our kitchen which might boost up milk production include milk, Jeera water, methi seeds, garlic, all green leafy vegetables, oatmeal, nuts etc. Try to include these in your regular diet. You can try some herbal tablets by name Lactare capsules (take 2 capsules thrice daily for 10 days). Formula milk is better than cows/buffalo milk, when you have to supplement extra apart from breastmilk. Stay motivated throughout. You will be able to see your wish of exclusive breastfeeding come true. Good luck.