Hi Zazzex, The meaning is that we each had a drink. A native speaker would usually say: You and I had a drink. Or, You and I drank a beer. If you wanted to say we shared a drink, then you would say it that way: You and I shared a drink, or you and I shared a beer.
Hi, These sentences could mean either two drinks each or two drinks all together, depending on the context, so you need to add a little more information to the sentences.
If each person has two drinks, you could say: We had two drinks apiece, or They had two drinks each.
If each person has only one drink, you could say: All together we had two drinks