The 53-year-old spent two years at St Pauli before the club dropped into the 2. Bundesliga, bringing his time at the Millerntor to an end.
Blessin has now admitted that the aftermath of relegation affected him significantly and that it took more than a few weeks to regain his energy.
“I needed quite a lot of time until I found my energy again after the relegation,” Blessin told the Hamburger Abendblatt.
“After the first week it wasn't better, and in the second it wasn't really either. It was only with the decision, when our paths separated, that I found inner peace.”
Blessin has since returned to the Bundesliga, taking charge of Borussia Monchengladbach two weeks ago after the club parted company with Eugen Polanski.
The former St Pauli coach now faces the task of rebuilding confidence around a Gladbach side that has undergone another change in the dugout.
He said his immediate priority was to reconnect the team with those around the club.
“The main task now is that we regain the trust of the people,” Blessin said.
“There is a lot of work ahead of us, but I am happy and pleased to have this job.”
The move gives Blessin another opportunity to establish himself in the Bundesliga after his previous spell with St Pauli.
His time at the Hamburg club ended on a difficult note, but the coach has now had the opportunity to reflect on the experience before taking on his latest challenge.
The relegation also marked a significant change for Blessin personally. Rather than immediately moving on from the disappointment, he acknowledged that it took time before he felt able to recover his energy.
His comments underline the emotional impact of the season and the eventual separation between coach and club.
At Gladbach, however, Blessin has quickly shifted his focus towards the demands of a new job.
Restoring confidence will be central to his task, with the coach recognising that there is considerable work required to rebuild the relationship between the team and supporters.
After the disappointment of his final weeks at St Pauli, Blessin now has the chance to write a different chapter in the Bundesliga.