Hi,
This is a very normal issue that many people go through. The thing you need to find out is what you are actually scared of. For most people it is the fear of being rejected. But, we have to get over that as we know catagorically that you will be rejected by some. However, they are not personally rejecting you. They don't know you. They are rejecting a concept and many people don't even stop to listen, so it isn't personal.
Logically, you know a lot of people WILL say no and, equally as logically, you know there are people out there looking for people like YOU that will welcome your call.
As an NLP/CBT life change coach, I get people to reframe the thing they are afraid of. So, rather than worrying about you and how you feel, reframe your thoughts and think of the call as something vital that people need and will benefit from. Focus on the fact that you ARE helping people, not asking them to mortgage their homes to use your service ;-) When you do this, you feel surprised when people say no, which is better than feeling dejected ;-)
Write down a structured script, something you can use as a base for calls. If someone says no, then simply say that's fine, would it be ok if I called you in 3 months to see if things might have changed. If they so no, great, move on. If they say yes, great, you now have a warm lead.
Set yourself a target to do, say, half a dozen calls. Don't focus on the outcome, just focus on doing the calls. Even if they lead nowhere, you have overcome the issue, so you know you can do it again, and again, until someone says YES.
When we push through our fears we feel alive. Don't hand it over to someone else. It's your business, so stand up and be proud of it and you.
Regards
Jan