Scott Allan expressed his regret after failing to help the Blues secure a victory during his latest loan spell.
The midfielder linked back up with his West Brom team-mates at training today.
His stint with the Blues expired following the 2-0 loss at Walsall on Friday night.
Allan impressed on loan at Fratton Park in the Championship last season.
But he failed to show anything like the same kind of form this time around in a struggling team.
He admits it has hurt him that he failed to taste victory even once during his second stint at Pompey – a club where he has built up a strong affinity.
Allan said: ‘I’ve had some great experience at Portsmouth both last season and this time.
‘They have great fan support, it’s a great club and I just hope the club gets itself sorted over the next few weeks.
‘It is the most games I have played for any club at senior level and I feel I have built up a real affinity for the place.
‘So I will miss a lot of people at the club and I really hope things work out.
‘But I need to get my head down at West Brom and see what happens there now.
‘It’s disappointing to leave, especially as I haven’t won a game since I’ve been here.
‘There are games we should have won and games where we have given away silly goals, so it’s disappointing from that point of view.
‘I would have liked to have done more but it’s a completely different style of football to what it was last season.’
Allan’s spell was not helped by a three-match ban following a red card against Notts County.
He admits he found it tougher in Pompey’s current side but believes he has gained some valuable experience.
He said: ‘You learn different things from different levels.
‘Last season in the Championship, I found it a bit easier to find people with passes and they were a bit more on my wavelength.
‘This season, I have found out a few more things about the other side of my game that perhaps I need to work on.
‘It’s not in the Championship but it has been valuable experience.
‘Hopefully, it will make me a better player in the future.’
– STEVE WILSON