It depends what you mean by 'is it okay?' It's certainly very common. There are many words in English that are hard to pick out (to pick out means to be able to hear them separately) in English when native speakers speak. In English certain words are naturally emphasized when people speak. For example, in the sentence "A box of matches please," you will probably hear 'box,' 'matches,' and 'please,' clearly but may barely hear the other words. If you know what the overall sentence means, then it doesn't really matter if you cannot hear one or two words. If not being able to hear those one or two words means that you cannot understand the sentence, then it will give you a problem.

You are right. We often don't actually hear the 'do' auxiliary, but be assured that the 'do' is there , even when native speakers are talking informally. We never drop the auxiliary verb, however informal the context. So, question such as 'What do you do?' will SOUND, to the non-native ear as 'What you do?'. However, what we are really saying is 'What d'you do?'. The 'd' and the 'y' merge together into a combined sound that is like the English 'j' sound in 'just'. This tiny sound very hard for many foreign learners to perceive, particularly Spanish speakers, so many people presume that we are dropping the 'do', or using some kind of informal grammar where the auxiliary isn't used. In fact, both the native speaker and the native listener is aware that there is a 'do' in the sentence, however imperceptible. Believe us - the 'do' IS there!