Levels dropping - depressed

Hi has anyone been hyper for a long time and when they started to drop close to range became extremely depressed? I have not gone hypo my last test was less than a week ago. I am still on 60mg carbimazole but I have become severely depressed and suicidal. This isnt normal and endo doesnt think its thyroid as I am still technically but I am so sad and it almost came on overnight. I dont know what to do