It sounds as though you would benefit from airing your troubles, to a psychologist probably, although confession probably works to some extent...
If you want to avoid contaminating the source of your world? Don't worry, it is also the source of your contamination...
If you want to be a better person, self-analyse. If you do not know what a better state is, and do not know the difference between your current state and that of the desired state, then any improvements will be largely random. You shouldn't expect to make a decent paper plane if you don't know what shape you want it and can't see the paper... Really, I inherently distrust any religion that doesn't preach self-understanding. The whole idea of "sin" feels to me like it is telling you what is wrong arbitrarily so that you don't need to bother looking at evidence or thinking about anything... Compare with things like Fox News that would get you caught up over how they are wrong about an issue and really win by having you ignore this other issue that they don't even mention or just drop and an inconsequentiality... Your sins probably haven't caused as much damage as you think and the damage you have caused probably had more contributing factors than you think.
Really, bad deeds are not a matter of the consequences they have. Humans are not equipped to know all of the consequences of their actions. Bad deeds are the result of failing to attempt to predict what consequences you are able to. You can have good intentions by spraying water at a cat to get it out of a tree, but whether it safely runs home, runs onto a road, plummets from the tree and lands badly, or climbs higher doesn't change the fact that you were probably acting with undue haste and a lack of consideration, but ideally the cat wouldn't have been stuck up a tree to begin with.
Minds are far less malleable than people think. With sufficient resources, it is possible to murder someone by compelling them to commit suicide. Advertising does have a measurable effect. Thoughts are not that important, it is all just a big mess of circumstance. Whatever bad deeds you feel that you may have committed were(most likely) performed by your own hands, but being the person that you were you didn't possess the means to act differently. All that you can do is try to mould yourself to behave better in the future, and that means self-understanding...
Also, consider that a great many very unhappy people have died, often in great numbers over a short period of any given dimension. There is a decent chance that any being that interacts with the dead has been displaced at some point... Maybe god number 38926 could benefit from your relative decency...