You'll get that "call" to do it eventually, and then you'll know the time is right. You'll just have that urge to do it, which may not pop up for a while, and when it does, you may still be scared, but you'll have the drive to push past that initial anxiety. When a trip gets tough, problems that follow afterward are largely a mark of resistance. In my experience, at the darkest, most terrifying, intense core of the experience, if you can patiently sit it out, taking note of what's going on and just let it do whatever the hell it wants, you'll often be pleasantly surprised at the resolution of the experience. Often times if I get a really dark, intense, nauseating, super fast trip, I know that if I'm patient and let the experience run its course, that all that pent up energy can completely make a 180 for some of the most blissful, light-filled experiences of all. I've had 3 godhead encounters in the past 3 weeks and each one was preceded by intense chaos. If I would have resisted the hellishly intense loops in the first place, I would have never seen the godhead, but because of my surrender and patience, once the loops seemed to start to lose their energy and intensity, the godhead would start to emerge (effectively taking everything in a very different, yet pleasingly more intense direction).