You should keep your great M6.
About what you feel: as most things in life, I guess your feelings on this have no reason, but several reasons acting together months ago... You've had repairs and changes, you can't see the frame alone as in SLRs, and you're learning RFs with an unusual to you focal length...
I recommend you to keep the M6, and also keep that small nice 35, and use them differently as soon as possible... For example, you could plan some new style shooting designed just for the pleasure of composing inside the frame, and also for very fast street shooting: prefocus your 35 at 8 feet, load ISO 400 film, set your camera at say 1/250 f/11 (yellow filter) and shoot for some days just under direct sun... Shoot scenes and subjects receiving sun: not too vertical sunlight, but the rest of it... This will make you enjoy your great camera and lens in a new and comfortable way: no need to focus, and no need to set aperture or speed... Just compose for fun when you want to, or just point and shoot when you want to...
I came to RFs less than two years ago, after 25 years with SLRs. Not seeing through the lens made me feel strange and very slow for almost a year, but now I feel great with RFs: they make me stay more in contact with the scene, more alert... I guess it's precisely because with SLR's we imagine we're in contact with reality just because we see through the lens, but now I'd say RF photographers are more in contact with reality because they really need to be like that all the time to be ready to shoot without seeing the real scene through the lens...
Prefocusing is not just fun: it makes us better photographers because we're faster and dedicate our minds to things away from technical skills... Go into the sun with ISO 400 for a few days an you'll see it...
Cheers,
Juan