OK. Take a deep breath and repeat: "I can do it."
Take one double-pointed needle in the same size (width) as your circular. Place DPN in your right hand. Count how many stitches are left on your circular, then divide by three. (So if you have 18 stitches, your answer is 6. If you have a remainder, come up with an answer sort of close; if you have 20 stitches, you can divide the stiches 6, 6, and 8 or 7, 7, and 6; whatever is most convenient to you.) With the circular needle in your left hand, knit that first number of stitches (about a third) onto your DPN.
Now: push the stitches you just knit into the middle of the needle, so there's plenty of room at both tips. This is so they don't fall off as you go to the next step.
Pick up the next DPN in your right hand. You've still got your circular needle in your left hand. Knit the number of needles you think should be on your 2nd needle from the circular to the second DPN. Again, move the stitches to the middle of the needle to keep them from falling off.
Do the same thing with the 3rd DPN and the remaining stitches.
Now all your stitches are on the DPNs. Sigh. Take a short break. You are fine!
Next up, take the fourth DPN, and knit the stitches that are on the first needle. The needle that was in those stitches originally is now free. Put it in your right hand and knit the stitches on needle 2. Keep going like this, using the just-freed needle to knit the stitches on the next needle.
Review Amy's videos on small-diameter circular knitting in the Advanced Techniques tab for more about using DPNs.
Hope that helps.