You aren't stuck at all.
Since you're at Meteor Falls, that means you have beaten Wattson and gotten the Rock Smash HM. Get your Pokemon with Rock Smash, and if you haven't already done this, go to Rusturf tunnel which is on Route 116. Smash the rocks in the way to get to Verdanturf town. This can take you to Mauville city, so you can go back to where you need to go.
Additionally, if you already beat Team Magma at Mt. Chimney and gotten your fourth Gym Badge, then head down to Petalburg city, beat your dad, and obtain your fifth Gym Badge so you can get HM Surf. After that, you can either go down to Route 103 and Surf to Route 110, or go to the water near Mr. Briney's house and Surf to Slateport city from there.
Hope this helped.