Losing alcohol tolerance in public settings?

I drink a few times a week (3-4 beers or 2-3 highballs with at least 2 shots of vodka in them), always at home by myself. I barely feel tipsy, usually I stop drinking and go to bed because I get bored or my stomach hurts.

I haven’t drank in public or in a social setting for a long time, although I also used to have a very high alcohol tolerance at parties/restaurants etc. But twice this week I went out to a restaurant, and had some drinks. At one restaurant I had two beers, at the other I had one cocktail. I was by myself both times so it wasn’t a “social” occasion, just drinking out of the house instead of in my room. Both times I felt tipsy fairly quickly. I could feel lightheadedness, impaired judgement and reaction time, and slight slurring of speech.

I was definitely getting drunk more quickly. Is it possible to lose alcohol tolerance over 1-2 years? And is it possible to maintain alcohol tolerance when drinking alone at home, but get drunk faster outdoors?