BigXThaPlug Arrested in Dallas on Album Release Day

BigXThaplug is in a Lone Star State of trouble after getting booked into Dallas County Jail Friday morning ... the very day he planned to celebrate dropping his new album!!!

Dallas PD tells TMZ Hip Hop ... officers observed a vehicle without a front license plate, so they pulled it over, and discovered the driver was 27-year-old Xavier Landum -- better known as BigX.

Things went south for the rapper when cops say they found a firearm and marijuana in the vehicle.

We're told BigX was arrested and charged with 2 misdemeanors -- possession of marijuana and unlawful possession of a firearm.

He appeared in court later Friday, and his team tells us he's been released.

The timing of BigX's arrest royally sucks for him -- the Texas MC released his rap-country hybrid album, "I Hope You're Happy," on Friday. While it's doing decent numbers on streaming services ... getting out and promoting it just got a little more complicated.