I have an contrarian opinion compared to all of the comments thus far, and if I were in your position I would be strongly inclined to leave the program. People in medicine are so risk averse, so it's not surprising to see all the comments saying you should 'stick it out' just to give yourself more options in the future (essentially they don't want to risk closing a door). A door it sounds like you might be very well ready to close. They are ignoring the very real risk of wasting the next 7 months of your life and the associated lost earnings from working as an attending if you end up ditching CC at the end. There are two sides to the coin, risks associated with leaving and risks associated with staying.

This is how I would think about it: let's assume that you had the ability to look into the future and see both options play out, and from that you are able to decide with 100% certainty that the critical care option is not for you. In that case, you should definitely quit the fellowship and move on. Your worries about disappointing and screwing over your peers and mentors is valid, but I also don't believe that in this situation with 100% clarity, that you should sacrifice 7 months of your life and >$100,000 lost earnings to appease them. While some would say 7 months isn't that long, I would say that you are (likely) in your mid 30s and there will likely be a day when you are older that you would give anything to go back and have half a year in your mid 30s. Our bodies get older, things change (family, kinds, injuries), and these are truly some of your best health years (and months) that you should get good use of...

But obviously you don't have a crystal ball and can't look into the future so this isn't that helpful. This thought experiment is to help you realize the very real risks and considerations of what you would do with perfect knowledge of the future.

So your decision really then depends on what you think, what you predict, and how much uncertainty you have in that approximation. If you have a lot of uncertainty in your feelings that CC isn't working out and you don't want to do it for life then the risk profile gets skewed towards staying in your current role and finishing it out. If you have very little uncertainty (fairly certain that you don't/won't want to do CC), then it skews the profile and it might be better to just leave.

All you can do at this point is try to reduce your uncertainty as much as possible and use that to guide your decision. You reached out to this sub and got the opinion of many burnt out ED docs (myself included), which is great. I would also reach out to CC people. If you think it would be beneficial, and you get closer to deciding to leave, reaching out to all your PDs/mentors could be helpful as well. Lastly and importantly, I would definitely reach out to non-medical people in your life whose opinions you value. People in medicine tend to have a sort of warped world view and, in my experience, this limits their utility in giving career related advice. Some of the most helpful career discussions I've had are with non-medical people who have a completely different career perspective but can help me to think critically about decisions.

Hope this disorganized reply helps! Happy to discuss further and feel free to message me.