From the little that i know, no it isn't good to go untreated. It can cause heart problems. I too have supposedly hyperthyroidism. But for the most part I feel hypo. The times that I did feel hyper, I felt the same way you did. I also have a 4 cm nodule in my neck. I'm having a hard time getting it taken care of because I don't have insurance. I have been going to my local clinic and pay $50 each visit. Seeing a PA is cheaper then the actual Dr., but they are still very good. The blood work was $120 for everything. If you tell them from the very beginning, most places will give you a discount. The Dr. thinks that my problem has been developing over a good period of time, but there is no telling. You might want to check your thyroid yourself and see if you feel anything. Being a man increases your chances of it being cancerous, so check it out now. I have gained about 30 lbs from this hunger and it isn't fun. Also if you are hyper and losing weight it is lost muscle, not fat. So if you are working out it probably isn't helping as much as it would normally. I'm not a doctor by any means, but I know how you feel. But I'm a female, and I can't work out because of my heart racing. Check it out, Don't take a chance. Good Luck!
If you ARE hyperthyroid-it would be very unwise for you to not seek treatment. You can have labs drawn, without doctors orders.
A good test, including TSH and Free T3 and Free T4:
It's $85.00 and with code 12345 it will take 10% off your order (-$8.50) I recall S&H being about $12.
Click on "view locations": http://www.healthcheckusa.com/ for a lab near you.
If your labs return pointing to hyperthyroidism, get your rear in gear and go to the doctors. That said, it would be a good idea [period] to seek professional help- if you are filling ill and distressed over it.