KMR,
For starters you reconize that NOW is not the time for distance; which is a good thing.
I seriously hope that you are taking an anti-depressant medication. If not see your doctor immediately.
Also, see your primary care physician for a Thyroid test, which can cause these symptoms as well. I pray that your test will be normal. Once the results come in; ask for your TSH #. If that # is above 3 but below 5, you may be ok if the anti-depressant is helping, but if you are suffering other symptoms of hypothyroidism, get a second opinion!
Next, assuming that being intimate will not hinder your husband's medical problems....
Hire a sitter for the night. Dress up, do your make-up or whatever it takes to get sexy. Go without you underware, or your hubby's favorite, but don't tell hubby until dinner or until the appropriate time. As a special treat, men are attracted to a woman's "natural scent", so put some of your "natural scent" on your neck. Essentially, you two are going on a date... show your hubby that you love him and do care about his feelings.
Keep in mind that foreplay can be an important key to love making especially in your situation. Encourage kissing, hugging, holding hands while you're on your date. Have him to hold the door for you, grab your waist or put his hand around your shoulder, while your out on the date. The key here is that he wants you and he's going to "put you in the mood", but keep in mind that you have to do your part too.
Go out for a romantic dinner. If you cant afford an expensive one, you two can split a entree, which many restuarants offer these days. And discuss with your husband how your're feeling. I suspect that you're tired and maybe depressed over money issues, but the love should never stop.
Good luck and hopefully you both will wake up refreshed the next morning. Please let me know how things go.
PS, have adult conversation and DREAM... don't discuss the kids, mom, dad etc. discuss how you feel what you want to do, how sexy your husband is to you, what still makes him special after 3 1/2 years, what you still love about him, etc. Pretend that you two are childless, and and that you're trying to win him over all over again.