Hey, I had thyroid cancer 5 years ago and firstly, the odds are very much in your favour as to it being benign. Thyroid nodules are very common and the vast majority are benign, I think like 95% of them are benign. Given that your doctor said it doesn't feel cancerous, the odds of cancer are probably less than 5% in your case. 

And I have never heard of usual bowel movements as being related to thyroid cancer, so it is very likely that is stress related or it could be just completely unconnected. Thyroid cancer rarely has symptoms, so if the doctors say your symptoms seem like stress, that is probably what they are.

I don't think there is anything really for you to do except wait for the appointment and see what the doctors say. If they have any concerns, they will send you for an ultrasound or a biopsy (and the odds are that if they do, they will find that everything is fine). If they don't have any concerns, then great. You should just try and put it out of your mind if that is the case, though I know that is easier said than done.

And in the off-chance that it actually is thyroid cancer, well, thyroid cancer is not what you may be imagining when you hear the word "cancer." Amoung younger people (where younger means under about 50), the most common forms have a survival rate of close to 100% and they don't tend to use chemotherapy or radiotherapy or any ongoing treatments. Basically, they'd just remove your thyroid and maybe some lymph nodes from your neck. Obviously no operation is exactly something you want, but it is very manageable.

This is especially true as your nodule sounds like it is really small. Mine was 10.5cm (yes, cm, not mm). And I was still back to my normal life about a month after my operation (and a month after that covid kicked in and none of our lives were normal for a while, but that wasn't related to the thyroid cancer!!).