"two days after the day b4 tomorrow" - the tomorrow and the day b4 would cancel out, leaving the "today" whatever it may be. The day before this is said to be Monday. Monday is 1 day after the current day, due to the 'day before these these days.' i.e.) 2 days("the 2 days after") minus 1 day("the day before").
If Monday is 1 day after the current day, then the day "today" would be Sunday.