Hi Sarah,
If you really think you have tennis elbow, I have a suggestion that worked for me. About 3 years ago I got a "free" lawn mower. I had to do alot of work on it to get it running, and I ended up pull starting it probably a hundred times. Several weeks later, my elbow became very sore, eventually to the point that even shaking hands was excruciating. I went to an orthopedic surgeon and was diagnosed with Lateral Epicondylitis (tennis elbow).
My doctor sent me to 4 weeks of physical therapy. It did little to nothing. My doctor gave me two cortisone injections over the course of about 6 weeks. That helped in the short term, but the pain returned. In digging around on the internet, I came upon an exercise using something called a Flexbar. I watched the video and ordered one from Amazon. I did the exercises religiously for about 2 weeks and started noticing an improvement. After a month, I was about 75% better. After two months, it was completely gone and has never returned. I still do the exercises regularly, just to keep the muscles and tendons in good working order.
Here's a link that describes the exercise and the Flexbar:
http://info.thera-bandacademy.com/flexbarelbow
The best thing is that if you continue to do the exercises fairly regularly, you'll be able to spank those monkeys without it recurring
!