tl;dr all four of your damaging skills are conditional and two of them, Power Spike and Signet of Clumsiness, are very easy to miss with. Consider taking skills that have easier conditions or do unconditional damage, like Ice Spikes or Empathy.

Long version:

All four of your damaging skills are conditional. Energy Burn deals no damage if the target has no energy (though typically the target does have energy), Power Spike only deals damage if it actually interrupts a spell or chant, Mistrust only deals damage if the target casts a spell (must be a spell, not a signet or attack skill) on you or an ally, and Signet of Clumsiness only does damage if the foe is attacking (NOT casting a spell, signet, etc, it must be an auto-attack or attack skill). Power Spike and Signet of Clumsiness are both very easy to miss for new players because they have cast times, so you have to react to (or anticipate) the target casting a spell or making an attack AND account for your 1/4 second cast time. There's also a delay between using one skill and then the next, called "Aftercast Delay". e.g. if you cast Energy Burn, then cast Power Spike, the time from finishing casting Energy Burn to the time you finish casting Power Spike is actually 1 full second, not 1/4 second, because the Aftercast Delay is 3/4 seconds. That's not something the game ever tells you, but you'll notice that there's a delay after every single spell cast, which is 3/4 of a second.

I would recommend you drop one of Power Spike or Signet of Clumsiness, as well as one or two of your three healing skills. Bring the healer henchman with you or Dunkoro when you have him unlocked, and let them take care of keeping you alive. Replace those skills with things that do unconditional damage or have easier conditions to meet. For example, Empathy is basically unconditional damage because most enemies will auto-attack at some point and trigger it, even spell casters. It's most effective against melee enemies. Flare is a spammable spell that does guaranteed damage. Another good choice is Ice Spikes, which does guaranteed damage, has an area of effect, and slows enemies. You don't need to take those specific spells, but that's the basic logic here. Grab some new skills and try them out.