There's no need to posit some ultimate objective terminal value to explain why you're terrified of choosing the wrong values.

First of all, if by "choosing the wrong values", you mean "choosing the wrong terminal values", then you're just not making sense, or rather it's just not clear what you're trying to communicate. Placing "wrong" next to "terminal values" in a sentence about you choosing what you want your values to be, sounds no different to me than saying, "That ball is square." I'm not in a position interpret either of those sequences of words.

A course of action can be wrong only by reference to a value. Or to taboo the word "wrong", a course of action can be incompetent only if you posit a goal the agent is trying to achieve. Driving into a tree at 70 mph is a bad idea for me only because I don't want to die or get crippled, and I don't want either of those only because X, and X only because Y, etc., until we reach my terminal value(s). Someone else may be different in this respect.

It's not possible to choose your terminal values, or rather it just doesn't even make any sense to say that phrase: "choose your terminal values". Choosing involves valuing. Once you choose something, you're choosing it because you think it's a good way to get something else, but then that something else is by necessity more "terminal" than what you chose. You can't choose your terminal values; you can only discover them.

With that said, I want to echo the others who mentioned that your situation may be the result of some basic physiological problem or whatever. All too often do people chalk their situation up to their personality, or How Things Are, or something like that, when the situation is extremely malleable, and is no more than the routine, methodical outcome of some basic lifestyle consideration or toxin exposure or whatever.

I've been in and out of many states and conditions over my lifetime that felt so urgent, or so profound, or something, but have in the end proven to be nothing more than what I mentioned in the last paragraph: the result of some lame environmental circumstance. For example, depression can be ridiculously severe, and color one's perception of the world in such an insanely pronounced way, that it seems so out of place to tell them, "Maybe it's just because you're not exercising." But sometimes the solution really is that mundane.

Big effects don't necessitate big causes. Or more to the point, intense mental states do not require intense events proceeding. As I started off the previous paragraph with, I've been in and out of so many of these intense mental states that proved to be lame circuitry misfirings (or whatever), that I have come to take my emotions with a serious grain of salt. I know your mental state isn't "intense", so I guess this is starting to sound a little bit centric to my own experiences, but I think the basic message is the same.

Having no values seems like a very boring existence, and Very Boring Existences are undesirable in comparison to exciting ones. This means that you don't actually have no values, and that saying you have no strong values is nothing more than an idiom. You do have values. So what you must do is figure out how to elicit those values, and maybe there's some simple physiological problem to blame. Perhaps try improving your lifestyle (e.g., diet, exercise, sleep, toxin avoidance), and/or try getting some sort of basic medical workup where you mention your lack of zest for life and so on?

Hopefully this was somewhat helpful. Good luck, and I hope you stick around Less Wrong!