Ha! The DEX lists "sandviș", "sandvici", "sanviș", while the DOOM lists "sandvici" and "sendviș" (there should be an agreement at least among them, but whatever). However, I also pronounce it "senviș" and a bunch of people I know, whom I've just asked, also use that pronunciation. I don't think I ever type it, though, but I would probably stick with "senviș".
not a case! It is the conugation of the word a avea (to have). Am means I have. I do not know your native language, but keep in mind that conjugation system is nearly distinquish in English, so they need to use personal pronouns such as I , YOU etc. And other languages mostley do not