I seek to discuss this point a bit and give you some tools to handle it so that what was once too much becomes manageable and well within your control. To this end, if you find yourself stressed out without an obvious cause, take some time to quiet the mind. When you've achieved that state, ask yourself "what's bothering me right now?" and listen for an answer, whatever it may be.
There are times where that fear or concern is entirely legitimate in nature, and there are times where that internal response is laughable. If its a valid reason to be concerned, the next thing you want to ask yourself is "what can I do to take steps to remedy this situation?" and again, listen for answer. Repeat this process until you have an idea of what needs to be done next so that you can make yourself more comfortable.
You might find yourself in a situation where you're banging your head against a wall because there's no end in sight, but that's going to be relatively rare. This rather simple meditative exercise gives you a tool to first determine what's upsetting you, and secondly gives you the ability to brainstorm and respond to that perceived threat in a rapid fashion instead of simply agonizing over it. As you then take the steps necessary to resolve the trouble, you should begin to notice less fear and anxiety in response.
If, however, the trouble is something that you cannot make mundane steps to resolve, can you, through magical works, begin to create a situation in which steps can be taken? If so, do that, and then begin to take mundane steps in conjunction with the magical remedies applied, as you'll then make it possible to work against what was once an insurmountably difficult hurdle.
Seems pretty simple when written out in this way, no?
If you, however, find yourself in a situation wherein the stress is neither valid nor useful, you can take steps to minimize the fear itself. To do so, calm the mind then mix together benzoin, sage, and neroli (or substitute dried citrus peels). Use a mortar and pestle to pulverize the mixture, and then place the mixture in a dish. Place upon it a candle, light it and say the words "Stress from within me, I acknowledge you and lessen the loudness of your voice. You are valuable and wanted, but I have heard your words and make this choice."
When the candle has burned down, take the herbs and place them into a jar. Fill the jar with oil and consecrate it. Whenever you find yourself in a stressful place of mind, anoint your forehead with the oil and then go back to focusing on your endeavors. This creates a mental link, a magical link, and a mundane link to the point at which you've taken action against your stress, freeing you up to use the aforementioned exercise to deal with actual stresses instead.
Just something to think through and work with. Its a surprisingly handy tool.