OK, so, I sometimes do this thing, where, when I get an idea, I first cast myself in the lead role under the name "Mia". Basically, this means that I can put myself into a certain situation but it's not really me. "Mia" changes each time I write. She can be confident and clever, or she can very sad and vulnerable. Eventually of course, I will give "Mia" a new name, a new home, and basically develop her into a completly fictional character with her own life. But by using "Mia" I manage to develop the emotions. I was just wondering does anyone else do that or is this really really weird and possibly an indication that I am slightly mad and need help?
All Characters are versions of self. The darker aspects of our personalities magnified. Our best traits;Characters in general are;
The people we are,
the person we are seen as by others,
The people we'd hate to be.
And the person we long to be.
There is nothing wrong with using yourself as a base, especially the way you seem to be doing it. just keep it up.
I have written a story before, with the names and characters being people I know (myself included) and each person had resemblence to people I know aha I enjoyed writing it but will change the names when I have done a second draft :)
We write - therefore we must be completely insane... I assumed that that was obvious to all ;-)
I suspect that there is a difference between using "self" as a basis of character and writing from a first-person perspective - especially in the way that you describe giving Mia significantly different attributes at different times.
As Jonathan says it would seem likely that there are fragments of each writer in their work. I think that that is inevitable. I don't think that it is a problem of itself.
Writing one's own feelings and/or experience as someone else might be a useful exercise for one's own self-understanding and (possibly) more - but I wouldn't think it a good idea to share it - possibly with anyone but an professional counsellor - if that were ever appropriate. There would seem to be always far too many risks in revealing too much about one's self in this way.
Writing from inside the eyes of a character can be an excellent aid to developing both their character and a main story. I use a form of this activity regularly in all my longer works. In a sense I write a short story for each significant character - and some insignificant ones. This can in fact switch the significance of a character in the main work. The important thing for me as the writer is that it provides background, a character's "reasoning" and temperament - among many other things. Much of this information is likely to never appear in the main work - but it really makes writing that so much easier.
Hope this helps.
(I still think we're all nutty as fruit cakes) :-)