Is this right for me?

I am a 37 Y/O female who has hypothyroidism. I started to take the 100mcg Eletroxin about a week ago. I have had half my thyroid removed several years back. I did not take anything for a long time because i lost my medical insurance. i ordered the 100 mcg off a website located in Canada without a prescription. It is round with acrease on one side and an "A" on the other. Can someone please tell me if I am taking the right stuff. My last doctor had me on 75mcg of Levothyroxine once a day.