I have already decided that, no matter what, I will not work on Shabbos. If you could, though, I would appreciate it if you could write to me and explain exactly why I should get myself fired...I am searching for peace of mind.
First of all let me tell you how significant what you're doing really is: you may not yet be perfect in your Torah observance (but then again, who is?) but you're growing. I firmly believe that where you happen to be in your Torah-life isn't nearly as important as which direction you're moving. And more importantly, you've already grown to the point where you're comfortable giving up a good job. There's nothing at all of which to be ashamed there!
So let's talk a bit about the purpose of Shabbos. According to Rabbi S.R. Hirsch, working (at any of the 39 categories of forbidden Shabbos activity) demonstrates your dominance and ownership of the physical world by manipulating its resources (example: taking a tree and converting it to paper and then to a space on which to store notes or taking nuclear energy and converting it to an electrical current to power your telephone). In truth, this is a dominance we've been allowed six days a week, but which we must relinquish to the world's true Owner on that seventh day so as not to forget that it's really His world and we're only guests upon it.
By resting on Shabbos, therefore, we're acknowledging (to ourselves and to the rest of the world) both that God created this world ("in memory of the creation") and that He is its active manager ("in memory of the exodus from Egypt").
Related to God's active management of His world: the Gemara (Beitza 16a) tells us that "a man's sustenance for the year are established (i.e., an absolute income limit is set) on Rosh Hashanah - except for whatever he spends on Shabbos and Yom Tov and on his children's Torah education." So we believe that what we'll earn this year (and the expenses that will eat away at those earnings) is pre-ordained. Working more or working less won't affect that amount (bearing in mind that we do have to make an effort). So if Shabbos expenses will even add to our "net" income, we can't expect that working on Shabbos itself would be necessary!
These are a few thoughts about the sanctity and purpose of Shabbos - of course there's so much more to it but I have neither the time nor the intelligence to transmit everything.
One thing is clear though: you're involved in a very great struggle and the wonderful choices you're making will make your life immeasurably better in both the short and long-term.