I use essential oils on a daily basis. I have largely moved away from tea tree oil, but it does serve it's purpose when used in a proper manner.
I wouldn't diffuse tea tree oil, but have you heard of Thieves oil? It's a blend of different essential oils and it works so very well in a diffuser.
My mom is a part of the Young Living company (she doesn't sell it, just uses her membership to get a discount) and I get my oils from her, but there are other companies that sell a similar blend OR you can buy the oils separately from the company of your choice. Here is a link to the Young Living oil and their ingredient list. http://www.youngliving.com/thieves-essential-oil/Thieves-Oil
Best of luck to you! Young Living also makes a Thieves cleaner. Great stuff! It's expensive, but I do splurge on it once in awhile. :)