You aren't stupid for being scared. We all get scared and I still find it hard to send out emails too (in fact I should have sent one out last week but I've delayed it haha). What is stupid is the fact that we beat ourselves up for things like this. It isn't a mistake you know. Only a delayed success. If you want we can help you write the rough draft of an email to send to him so you just have to copy and paste it and click the button

It's okay to be terrified - heck, I'm terrified most of the time. But don't let that stop you from keeping on reaching out.
And as for feeling like a burden, all I can say is that you aren't. The harder part is to believe it though. We all want to be the person helping others but we forget that there are times in which all we can do is accept the help and love until we can stand up again. You're just going through a rough patch. You need the support so don't be ashamed of taking it