Having dealt with a ton of rejection letters I know that they are not personal. You have to know that too! Most publishers and editors are swammped with new writers that dream of being the next Stephen King or Laura Roberts. They are buried with query letters and a ton of paper from new authors that do not read the submission guidelines. One way to make sure your work never gets even a second look is by telling the people you want to publish your work that you did not read their guidelines for submissions. Send only what they ask for and do as we all do and wait for a reply. Time is what it is and that is the pain and suffering you have to endure as a writer to find out if somebody is willing to take your work on.
I tend to double check my sources for submissions to Lit Agents and Publishers. I get the written and published guidelines and double check on line to see if they have changed their requirements. Small Publishing houses can become huge avenues for writers if they sell one succesful book. Same goes for Literary Agents. One book makes the world beat a path to their door.
Don't give up hope though! Somebody out there is in tune with your writing. You just have to have the heart that is strong enough to toss all those rejection letters in the trash. Make another list to submit your writing to and do it all over again. Sometimes I get letters back that are personal and I appreciate the effort the person put into it. My work isn't bad, it just doesn't fit the house or agency that I contacted.
Many writers get depressed about rejection letters and I can understand that line of thought. It sucks to open that self addressed letter. Get passed that moment and move on. I look at it as someone on the road flipping me the bird. It doesn't ruin my whole day. Keep the faith in your craft and keep writing.