Hey Seetie!
You stop worrying about me, you didn't know, and right now I'm more concerned about you! I read your other posting about your sleep problems...what a pair, huh?
You're too young to be so ill, may I ask how long you've had the IC? Is the pain mostly from the bladder spasms or hardening? Last question, do you get any relieve from Vistarile or Atarax, if you're even taking them?
I do know that the best anti-depressant in your case is Elavil, but you mentioned worries about water retention, but it is the best for IC, because it not only blocks spasms and pain, but would also help with sleep, or should, but on low doses! You got alot of good advice {Gramps is awesome}, all anti-depressants are different and people react differently to them, plus they are no "magic" happy bullets!
It takes a good 4-6 wks. for people to really see/feel a difference!
The up-roar about Cympalta is bunk, just like Lyrica, the
RX companies promise they now have the "magic bullet" for us, getting hopes up, etc. it's plain horrifying! Hon, none of us wants to be popping pills, especially for the rest of our lives {I was always a health nut} and I tried to handle my pain holisticly, but I had to have my dentist, of all people huh, sit me down and say, I'm never going to be who I was as far as my body, embrace the changes even though it sucks (his words) 
and do what you can and that means asking for help too!! That's the hard part for most of us! So, if you need to take an Oxy for the pain DO IT HON!
Back to anti's...if your sensitive to meds. or prone to depression that effects your sleeping, they might not be for you and even make symptoms more sensitive/worsen!
Like someone here said, and it's true, drs. are handing them out to everyone for everything, blaming our CP on depression, duh 
, sorry it just makes me mad...like we don't have a reason to be sad or low!!! But, there is the% of those who swear by them, the chances are 50/50. For years the drs. have played this game with me....I've tried them all and each of them cause terrible side effects, even made depression worse, but remember that's my body that is sensitive to them!
One more thing...I need to rest...pain is screaming at me!
Have you ever tried Xanax? It not only helps some for pain, but also for sleeping, with good results 
!
Well, sweetie, hope this has helped some...there are options, plus you can call on me anytime...OK?
Sorry,for the rant...get back and we'll chat some more,
Blessings, Funnygirl