Perk exp resets after logging off!

[Archetype2589]

Last night I spent a few hours levelling up my support perk, starting at 187K shotgun damage and making it to 418K by the end of the session (i didn't really check the welding exp). I also passively levelled medic to level 2 during the session. I logged off for the evening as normal but when i logged back on today my medic was back to level 1 and my shotgun damage was back to 187K.
This has happened before with smaller losses of exp and i'm getting tired of how slow it's taking me to level my perks.
Is there any way I can get this exp back? Or can something at least be done to prevent this happening in the future?
Thanks

P.s. my killing floor nick is 'Archetype' and steam ID is 'Archetype2589', I run the game on a Macbook pro, currently on a cable connection in central china

[Bobdog]

Were you playing on a server with mutators? Greylisted mutators will make it look like you are gaining EXP when you actually aren't.

[Archetype2589]

nope, I wanted to lvl so made sure it was all whitelisted. a few different servers, mainly west london, farm and mountain pass maps(mostly normal, a couple on hard), no mutators as far as i was aware.