I have had my thyroid gland removed and after the surgery they don't put you on meds for almost 5 weeks. That is to get all the natural hormone out of your body and then I had radioactive iodine to kill any remaning thyroid cells.
If the issue is that your W is not producing enough thyroid, I can tell you that it makes you feel like you've been hit by a train. It is an effort to take a shower. I had to take a nap after putting clothes in the washing machine. Now I may be a bit extreme as mine was totally removed and perhaps you W is just low.
Imagine how you feel sometimes when on Tues you make plans for Saturday. Then Sat comes along and you just don't feel like doing that any more. Times that feeling by 1000.
So the sex drive can be impacted. Be patient, as the meds take a while to build up. But once it is there, no more problems. It really is a pretty standard thing to correct. And most people who are on meds don't have any problems or need to adjust meds up or down.