Help!!! Baby started waking up at night

My son was EBF 6 month, then I introduced him baby purée. But mammas milk still his first source. The problem is that now at 7.5 month he started waking up during the night, he used to sleep from 11pm to 5 or 7am. Now he wake up crying at around 1 or 2am put himself in crawl position and start crying (he just learned the position a week ago. If I take him and nurse him he will eat and fall sleep, if not he will cry until I take him. This is driving me crazy, hubby said that maybe my milk it's not making him feel full that maybe I should give him formula. I need advices please. Thanks a lot.