Your main problem here, Zina, is the verb form. Both of your sentences are wrong. You either need to say Who do you go with? (for a regular or repeated event) or Who are you going with? (for a specific event in the future) In modern everyday English it is normal to put the 'Who' at the beginning of the sentence. If you have an old-fashioned grammar book (or an old-fashioned teacher!), you may have learnt that 'With whom do you go?' is the correct form. It is, but it sounds awkward and unnatural to the modern ear.

"who are you going with?" or "who do you go with?", if you use the verb TO BE you're supposed to use the ING FORM.

Like Lanny said, it's probably either "who are you going with" or "who do you go with". The way you wrote it is not gramatically possible and these two are. But we can't give you a definite answer without any context. "Who are you going with" is typically a question for someone who has plans to go somewhere and the person asking wants to know if they are going alone or with someone. "I am going to the beach tomorrow." "Who are you going with?" The -ing form is most commonly used for actions that are taking place at the moment of speaking (I am typing right now, answering your question, sitting at my computer), but it can also be used for future actions that are planned, scheduled, agreed upon in advance such as meetings, dates, visits to a doctor etc. "Who do you go with" sounds like a question you would ask about a general thing, some action that happens on a regular basis. "I go shoe shopping every weekend." "Who do you go with?" It's like a habit or a common occurence.