In that case, Tara, you've got nowhere to go but up. ANY tent will keep dew and rain off you. And you don't need anything exotic. I'd suggest something like the Sierra Designs Clip Flashlight ($189), which is a great lightweight shelter for two or an ideal solo shelter. It weighs only 3 pounds, 13 ounces, so carrying it is not a problem. REI's Clipper ($169) is another good, inexpensive, and lightweight two-person tent. It's also "free-standing," meaning its poles support its shape, whereas the Clip Flashlight must be staked out (technically speaking, so does the Clipper so it doesn't blow away in a strong wind, but there is a structural difference). Or, if you really want to be by yourself, get an MSR Zoid 1 ($180), a terrific lightweight shelter for the solo camper.
Take some time at home to set up your new tent a few times to ensure you can do it in the dark or quickly if it's raining. I usually recommend a ground cover to go under the tent; cut a patch slightly smaller than the tent floor from inexpensive polyurethane sheeting (available at hardware stores for about $6 per roll). After use, dry the tent thoroughly, clean dirt off with a damp sponge as needed, and store somewhere dry in a loose, breathable bag (a cotton pillowcase is ideal). And have fun!