Girl, I'm the exact same way. I have a soon to be 3 yr old and a 14 mo old and it's almost a burden for me to have sex. It's totally hurting our marriage. I went to my OB/GYN for my yearly exam and told him how I was feeling. He took blood work and checked my hormones along with my thyroid and low and behold...my hormone levels were normal but my thyroid level was abnormal. I'm now on meds to help regulate my thyroid. Even though your thyroid helps regulate your metabolism, it totally effects so many other things when it's not working properly including fatigue, dry skin, anxiety, depression, brittle nails, low sex drive. So, it might be worth checking out. Believe me, I have tried the romantic dinners, candles, etc. It didn't work for me. My husband would say, "what happened, you used to be so sexual". That doesn't make a person feel real good. Anyway, I haven't been on the meds very long, but I do feel a difference. More energy and will to do things that I haven't felt doing before. Hopefully this helps and just know that you're not the only one out there that feels the exact same way.
Good Luck