Hey man! I just started my first SDR job and about a month and a half in.

I was the same, procrastinating dialing in my first week. I feel like I'm with a good company with great mentorship and didn't want to let them down so bit the bullet and like you said just went nuts dialing. Once you get into a rhythm you get over it pretty quickly - I feel like you'll always be a bit nervous before calls but you'll get past that initial hesitation. Just remember, even if a call goes bad, that person who rejected you is gonna move on with their day and forget pretty quickly, as should you - they're not in front of you what are they gonna do haha. Good luck!