Hi Bla2886,
Considering the reluctance Dice have had with returning PVE to Portal, I don't think that we'll get the ability back, so it's probably best not to expect being able to play Redsec solely against bots officially to avoid disappointment.
I feel I have to say, however, that if playing the game is genuinely making you "sicker and sicker of the game and life itself", it'd possibly be worth considering playing something else for a little while. Games are meant to be fun and shouldn't trigger depression.