Striker Adam Idah was among those to come on following his deadline-day move from Celtic, though the Republic of Ireland had little opportunity to impress in the final third with Swansea on the backfoot by the time he entered the fray.
Asked how Swansea can reach their top level, Sheehan added: “We have had a lot of change in the summer. I think it’s foundations and building and consistency.
“Ultimately we are 2-1 up after 96 minutes – I don’t know where that time came from – but to concede in that manner is disappointing.
“When you are ahead after 96 minutes, no matter what happens we should see out the game. If we do it’s a wonderful battling win. If not, it’s obviously disappointing to concede like that.”