I was so terrified to get Mia spayed but did a little research and found out the horrible things that can happen to females who aren't spayed. I also spoke to several vets and those problems such as mammary tumors and pyometria are not just a possibility, they are very real and deadly, not to mention painful. I just knew I had to put her above my own selfish worries.
Mia is still under 2 lbs at a year old and she did just fine, you just have to do your research on toy dogs and anesthesia, as well as ask lots of questions of your vet!
I just added sections about these very things to my website for more info if you want to check it out:
http://www.mylittlemia.com/spaying.html and
http://www.mylittlemia.com/yorkiecare.html#anchor_48.
I know its so scary but afterwards you will feel so much better!