Where is this smoke smell coming from?!?

When I first moved into my apartment I didn’t notice any smells, but after awhile someone told me I smelled like cigarette smoke. I can’t notice it when I stay there as my nose becomes accustomed to it, but if I go away for a weekend and come back I can smell the odor when I first walk in. I can also smell it on the clothes I bring with me when I go away. My room is the only one in the entire 4-bedroom apartment with this smell, and I have no idea where it’s coming from. I had an ozone air purifier and it helped a little but didn’t eliminate the smell, plus it made my room smell like weird ozone. I bought a HEPA air purifier with a carbon pre-filter, but that didn’t get rid of the smell either. I also bought a box of Arm & Hammer Odor Eliminator for carpet and room and let it sit on my carpet for an hour before vacuuming it up. I almost suffocated myself with the overwhelming smell of that, which lasted for a couple days, but after it dissipated my room went back to smelling exactly as it did before. I’ve tried keeping my window and door open, but still my room smells and is the only place that does. Is it possible it’s in the carpet and walls and the apartment somehow managed to mask it for a couple days when I moved in? Or could the smell be in the new furniture I brought with me (i.e. the bedframe, desk, etc)? I loathe the smell of cigarette smoke and I have no idea what could possibly be causing it. How can I get rid of it?!
My neighbors don’t smoke.