Lionel Messi Having Serious Doubts on Soccer Future After Dad's Death

Lionel Messi is heartbroken over his father's death ... admitting he has no idea how to move forward without him -- on and off the pitch.

Jorge Messi -- who also served as Lionel's agent -- passed away in Argentina last weekend after battling an illness ... and the soccer superstar shared a heartfelt goodbye on social media.

"Dad, I still can’t believe you’re gone," Lionel said. "It hasn’t sunk in, or rather, I don’t want it to. It’s very difficult for me to imagine that I won’t see you anymore, that we won’t talk anymore. I know you were suffering and that it’s for the best, but you left too soon. We still had so much to enjoy together."

Lionel revealed it was Jorge who pushed for him to play in the recent World Cup ... but unfortunately, his condition worsened right before the tournament. As a result, Lionel said he did everything in his power to get Argentina to the final ... in hopes of allowing his father the opportunity to watch him play one last time.

"I wanted to win it so I could take it to you and show you a new one. I couldn’t; my legs had nothing left," Lionel said.

Lionel said he is now lost without Jorge ... and he has "serious doubts that I'll continue [playing soccer] for much longer."

"You were by my side from the beginning; there was so little left until the end. Why couldn’t you hold on just a little longer so we could finish together?"

Lionel reminisced on all the sacrifices Jorge made to ensure he could pursue his dream ... including all the practices and games he attended over the years.

"I'm going to miss you very much, but you will always be present, especially in the education of my children, because I teach and raise them as you both did with me," Lionel said.

"Rest in peace and look after us from above as you did here. Thank you for everything."