The loss dropped Liverpool to fifth place, with the risk of being overtaken by Bournemouth and Brighton & Hove Albion in the race for a top-five finish.
Villa exposed Liverpool’s defence repeatedly, scoring four, as the Merseyside club slumped to a 12th league defeat of the season, taking just one point from their last three games.
"It’s just frustrating because it’s lapses in concentration," Gomez, 28, said in an interview on the club's official website.
"It’s fine margins in the Premier League and that adds to it (the frustration). It is what it is now, we cannot sit here and feel sorry for ourselves, we just have to do the job.
"We know what we have to do next weekend and we have to beat Brentford at home."
Liverpool have struggled to build on last season’s domestic success and are set to finish the campaign without silverware under manager Arne Slot.
"We know we have to give the supporters something to support in how we play and how we approach the game," Gomez said.
"Hopefully we end the season on a positive note - that’s the goal."
Liverpool host Brentford on May 24th.
Check out the match report from Friday's defeat with Flashscore.
