Large amounts of spam suddenly coming through Contact form

Hi.  I am getting a lot of spam all of a sudden, since last Saturday, from my contact form.  I’m not sure why.  When I looked up this issue in the forum, it seemed as though perhaps I may need a site refresh for an update of the reCAPTCHA module?  Do you think that would work or is something else going on?  I don’t actually know how to check whether reCAPTCHA is on the form but the module is turned on on my site. 

Since I originally wrote the above, I did some more research and I installed a math CAPTCHA.  I am hoping this will help, but I prefer not to have legitimate people need to take the extra step if they don’t have to.  What do you suggest?

Thanks!