WASHINGTON — U.S. Rep. Aaron Schock, R-Ill., dogged about irregularities in his campaign finance and congressional spending accounts, suddenly announced today that he will resign his House seat at the end of the month. “I do this with a heavy heart,” Schock said in a statement in which he said he had given the people of his Peoria-area district his all since his election in 2008. “But the constant questions over the last six weeks have proven a great distraction that has made it too difficult …