You don't magically get better if you end up with heavy metal poisoning. Without treatment, it tends to remain in your tissues permanently. (However, life is chemistry and there are some foods that can promote the removal of metals, such as cilantro which is commonly found in Mexican fare.)
My guess would be the old building had mold or fungus issues. If you are otherwise in good health and don't wind up with a bona-fide fungal infection, moving out of such a situation would go a long ways towards resolving your issues.
http://articles.chicagotribune.com/1996-09-21/news/960921009...
https://www.neatorama.com/2012/10/15/Salem-Witch-Trials-The-...
You were probably just pissed off that you lived in a shitty apartment building.
So if the only factor in aggression is the amount of lead in the body, then we would have to assume it takes time for the symptoms to subside as well.
This can also be seen in big fish such as Tuna, which eat lots of small fish (which have consumed various heavy metals) and live for many years.
For most of these old toxic things, where plausible, the best option is to just seal it and leave it alone.
/s
The guy who invented lead-in-petrol also invented CFCs. He also died quite horribly from some contraption he made to hoist himself out of bed.
The downside to not having lead in petrol is that the raw material for the disturbing U.S. movies of the 70's has gone away, so if 'Dirty Harry' was made today then the rogues in it would not be as plausible.
You've pretty much described every old house in the US.