SEO nerd. Worked with LinkedIn, Dropbox, Avis, Expedia and many more big names expand their reach.
If it's not working for you, then don't do it! Focus on the outreach methods that are working and delegate the rest.
As a fellow introvert, I understand where you're coming from and I hate cold calling. That's why I hired someone from the Philippines who does it for $8/hr.
If you don't have any budget at all, let other people do the work for you and give them a commission.
Sales representatives, affiliate marketers and referrals are all great ways to increase sales without sacrificing your mental energy/health.
I wish you the best!