Josh Allen's GF Pens Mushy Note To Bills QB After Playoff Exit, 'I Love You'

Josh Allen's girlfriend is trying her best to cheer up her man following his heartbreaking playoff loss Sunday ... telling the Bills QB how proud she is of him despite the defeat.

Brittany Williams posted the mushy note to the Buffalo star on her social media page Tuesday -- just days after the Bills fell out of the playoffs following an overtime loss to the Chiefs -- commending him for finishing his fourth year in the NFL.

"It's amazing watching you put your head down and work every day to be the best teammate, leader, and football player you can be," said Williams, who's been dating Allen for years. "Through the ups & downs of this season, you remained calm and confident and it showed every time you stepped on the field."

She added, "I really don’t know how you balance everything, but you always do it with a smile on your face and with the biggest heart."

"I love you ❤️"

Allen will no doubt appreciate the words ... because he's got to be one of the most heartbroken people in the country at the moment.

The 25-year-old played his ass off in the Bills' game in Kansas City ... and came up just short of moving his team into the AFC Championship game against the Cincinnati Bengals.

He's got a good chance of getting his team there next year, though, 'cause the Bills have surrounded him with a bunch of talent.