A friend of a friend recently asked me for some advice. She has written six books, but none have been traditionally published. She's self-published the last two and feels they are good enough for the big guys to pay attention. I gave her the following advice, which I think would apply to an awful lot of aspiring authors out there. Hope this helps.
Given your situation, here's my advice.
Keep track of who responds (I used a spreadsheet) and then throw away or delete the rejections. Negative thoughts are not allowed. You are an author. You just have to make the rest of the world realize it.
And nobody is going to do that but you.