There seems to be a common mentality in the culture of board games that resigning is dishonorable or anti-social or "unsportsmanlike". This is emotional abuse.
When you agree to play a game with someone, you're agreeing to play until an outcome is determined, because that's the whole definition of a game: a system of rules that defines an end condition and assigns each player some sort of victor or loser status based on their decisions. If the victor is determined, the game is over. Games are consensual agreements made in the interests of fun, and once you've fulfilled the stated agreement, you are absolutely not obliged to continue something you don't enjoy. Defend Your Right To Resign.
This happened to me about a year ago. I had an experience playing Dominion where I completely ruined my chance of winning in the first two turns by misunderstanding one of the cards that was new to me. That time, I let the social pressure control me and played on without complaint until I somehow managed to come in second-last place despite my enormous blunder. The entire game was miserable. But complaining and not ending up leaving would have made it more miserable.
I reflected on this experience, and I decided it wouldn't happen again.
Some time after, I was playing Codenames with the same people. I was spymaster. My team fell far enough behind that we obviously had no chance to win except by the opponents guessing the assassin on a fluke. So I Resigned.
And of course, everyone was upset and tried hard to guilt me into continuing. But no. I wouldn't be abused.
(Ironically, I offered to play a second game but the other player who had tried hardest to guilt me outright refused to play with me unless I would promise not to resign. So it was his fault we didn't play another game.)
I never felt anything but incredibly satisfied with the decision afterward. I stuck up for my rights. And now it won't be hard for me to do it the future.
I'm writing this so that if anyone ever reads it, they'll have the encouragement to stand up for themselves too. Don't let inconsiderate and selfish people guilt trip you into doing something you don't have to do. Defend Your Right To Resign.
I should say that some people probably would be happy to let you and don't realize the social tradition is oppressing you on their account. Clearly my own group didn't fall into that category. But yours might. So give them the benefit of the doubt.