Can I straight breastfeed?

My baby is 7 months, almost 8 and he refuses formula, solids, rice, oatmeal, barley, snacks, everything! I tried just about everything, bottles, sippy cups, etc. The weird thing about this is he accepted all of the above until he turned 7 months. Like literally, the week before his "birthday" or what have you, he was drinking breast milk out of the bottle, formula, eating rice from spoon, etc. They say its a faze though. He's getting older and I want him to get his nutrients but he only nurses!!! What shall I do? Is he fine without solids and formula and all?