Its very easy to fix this if you have unlocked all the medic stuff. I would recommend doing this ASAP before valve patches this unlock thing, and possible taking out this fix in the process.

here is a list of console commands to undo individual achievements, if you copy these into notepad, and save them as a config file (in the correct directory of course) you can exec it in the console and fix a bunch of them all at once. If you earned some of them on your own before you used the unlock command just find the command for the achievement(s) you earned, and delete them from the list before you save it as a cfg.

achievement_reset TF_MEDIC_TOP_SCOREBOARD
achievement_reset TF_MEDIC_HEAL_UNDER_FIRE
achievement_reset TF_MEDIC_SIMUL_CHARGE
achievement_reset TF_MEDIC_SETUP_CHARGE
achievement_reset TF_MEDIC_RAPID_CHARGE
achievement_reset TF_MEDIC_COUNTER_CHARGE
achievement_reset TF_MEDIC_SWITCH_TO_MEDIC
achievement_reset TF_MEDIC_SAVE_TEAMMATE
achievement_reset TF_MEDIC_CHARGE_BLOCKER
achievement_reset TF_MEDIC_ASSIST_MEDIC
achievement_reset TF_MEDIC_SYRINGE_SCOUTS
achievement_reset TF_MEDIC_BONESAW_MEDICS
achievement_reset TF_MEDIC_ASSIST_HEAVY_LONG
achievement_reset TF_MEDIC_ASSIST_SCOUT
achievement_reset TF_MEDIC_ASSIST_PYRO
achievement_reset TF_MEDIC_ASSIST_HEAVY
achievement_reset TF_MEDIC_ASSIST_DEMOMAN
achievement_reset TF_MEDIC_ASSIST_SOLDIER
achievement_reset TF_MEDIC_HEAL_ENGINEER
achievement_reset TF_MEDIC_ASSIST_CAPTURER
achievement_reset TF_MEDIC_HEAL_CALLERS
achievement_reset TF_MEDIC_EXTINGUISH_TEAMMATES
achievement_reset TF_MEDIC_ASSIST_VS_NEMESES
achievement_reset TF_MEDIC_KILL_WHILE_CHARGED
achievement_reset TF_MEDIC_BONESAW_NOMISSES
achievement_reset TF_MEDIC_HEAL_LARGE
achievement_reset TF_MEDIC_HEAL_HUGE
achievement_reset TF_MEDIC_HEAL_GRIND
achievement_reset TF_MEDIC_KILL_HEALED_SPY
achievement_reset TF_MEDIC_SAVE_FALLING_TEAMMATE
achievement_reset TF_MEDIC_CHARGE_JUGGLE
achievement_reset TF_MEDIC_FREEZECAM_RAGDOLL
achievement_reset TF_MEDIC_BONESAW_SPY_CALLERS
achievement_reset TF_MEDIC_CHARGE_FRIENDS
achievement_reset TF_MEDIC_INVITE_JOIN_CHARGE
achievement_reset TF_MEDIC_HEAL_ACHIEVER
achievement_reset TF_MEDIC_ACHIEVE_PROGRESS1
achievement_reset TF_MEDIC_ACHIEVE_PROGRESS2
achievement_reset TF_MEDIC_ACHIEVE_PROGRESS3

NOTE: after using these commands, you will still have the weapons available at the loadout screen. Just select the normal weapons, then close and reopen the game, and you will be back to normal.

Hopefully this info helped someone, and like I said... im sorry if this has already been posted.

April 30, 2008 - Team Fortress 2 Update Released

Updates to Team Fortress 2 have been released. The updates will be applied automatically when your Steam client is restarted. The specific changes include:

Team Fortress 2 Client

Removed TF2 achievement console commands


Team Fortress 2 Server

Fixed clients being able to trigger sv_soundscape_printdebuginfo on the server
Fixed potential "nuke" exploit in rcon subsystem