I lose most memory of a night out after 2 pints while still being sober. Normal?

This is a recent development in the last 3 months. It takes me 5 pints on an average day to get kind of drunk (20F, 5”10, 70kg) and my friends attest for that. But now, I lose my memory from pint 2 despite being pretty much sober. I retain a few tiny snippets of certain moments and a lot of them I can tell Im sober. My friends are concerned because theyre also telling me I didnt even get drunk when these memory loss events happen (its VERY obvious when im actually drunk). I dont drink too often for a student compared to my friends, atm maybe going for pints once a week and every few weeks ill drink at a club. Is this concerning or nothing to worry about?