Saints are on course for relegation, sitting 10 points from safety with 14 games left.
Ramsdale suggested the squad let former boss Russell Martin down and spoke of a sense of “imposter syndrome.”
“It’s been really hard. Speaking for myself, I signed for the football club and a big part of that was Russell Martin. We let him down as a group of players,” Ramsdale told Sky Sports.
“The inexperience of Premier League football at the start of the season (meant there was) a feeling of an imposters syndrome or that we were inferior.
"It is scary when you go to St James’ Park away on the first day of the season. We are in one of the toughest spots any Premier League team has been in.
"Don’t get me wrong, I’m not sitting here saying we are going to stay up or we are going to do this.
“But while it’s still mathematically possible, the overriding feeling is positive because I’m seeing what these lads are trying to achieve.
"Nobody is sulking, which is very easy to do because we had been on six points for such a while, we are now on nine.
“Nobody is happy about that. We are all ashamed of where we are but we are on nine points and we have a chance to build on that each week.
"The good thing about football is there is always a chance for the first of something. As long as it’s not the first for something in a bad way, we have got the chance to make something amazing.”