Sometimes a fun thing to do is to take a "day off"off your life,if you can, and then go and do whatever(witin reason and possibilty,of course!)you want to do: go and buy something you've wanted for a long time, or that you just see and fall in love with, get a massage, a manicure, buy some candy or flowers for yourself, go to an aquarium or an airport or a cafe all by yourself and just look at the faces of strangers passing by, each one connected to their own, inherent,separate little universe, and yet,in their odd way,connected to you,also. Doing this always helps remind me that I am not alone in my aloneness, nor is my world this one's center. There are always others to reach out to: you could volunteer at an animal or a homeless or a domestic violence shelter; there will be always people out there happy and grateful for your presence.
When I think "frumpy,"I think of being uncomfortable and unhappy in my body, which for me too is often also the case. One thing I do to try and prevent that awful feling is some form of excercise I can connect to,on a deeper level than just my body:something that interests my mind also. You might try a yoga or a modern dance class, walking, a hiking group(such as the Sierra Club) or just rent/buy an excercise video you like and try it out around the privacy of your own home. Excercise really can be an enormous mood lifter--fun excercise that is!Maybe just make up the dance steps all by yourself. Be creative to have that much more fun.
Another mood lifter can be calling or writing a friend you've fallen out of touch with for a while, or taking a good friend or family member out to lunch,and explaining to them you are feeling a little depressed. Knowing you personally, they will probably be full of reassurances and good ideas to terminate this sad mood(obviously much better ideas than mine)and just the interaction and "confession" with loved ones itself can be very comforting and even uplifting.
Also,always remember: you are the one who perceives yourself to be frumpy, but no one else does! It is your self-conscious secret, not some noticeable fact. Anyway, maybe just try one day living as though you didn't feel frumpy, and see where that takes you--?
I hope you feel much, much better soon, and your painful feelings of "frumpiness" let go of you, SOON, setting you free from that terrible cage.