County were 2-1 up after a first Notts goal for youngster Tyrell Waite and a Krystian Pearce strike which came either side of a cracking leveller by John Fleck.
However, the Sky Blues were rewarded for their late pressure against their tiring hosts when substitute Franck Moussa secured a point with an 87th-minute equaliser.
Kiwomya admitted that he was frustrated not to record a final-day win.
He said: "We were out on our feet and we just tried to hang in there at the end. We put a lot in last week in the win at Doncaster and you could see we were struggling.
"I didn't have any other strikers available so when Tyrell Waite came off I didn't have any strikers to come on to take the pressure off.
"Their goals were disappointing. We gave Doncaster nothing last week and put our bodies on the line so it was frustrating to lose two goals like that."
Kiwomya added that the work had already started on shaping a new team for next season.
He added: "I'm starting to rebuild now and I will change the face of the team and try and get a team that can play.
"I've found out one or two things about the players we've got here so that helps make decisions. I've been watching other games and looking at other players who I think can fit in with this team."