Numbness in penis - thyroid related ?

3 months ago I was diagnosed with hypothyroidism, they started me on a 25mg dose, upping to 50 the next month and then to 75, around the time they upped me to 75 I started to suffer from the inability to get a full erection a lot of the time, I can still have sex, but I can't feel it much, I barely even feel anything even when I "come"

I know what the problem is, I feel very numb in my penis all of the time now, it's not easy to get a fully hard erection when you can barely feel yourself down there. What can I do about this problem? I'm not sure if my thyroid is to blame but this problem didn't start until 2-3 months after I started taking thyroxin. I wonder if it's even possible that the thyroxin tablets are causing it.