I'm looking for some advice on Olaf.

Olaf is by far the funniest champion I have ever played, however I'm having a bit of trouble winning.

In the laning phase I do really well. By the time laning phase is over I have 1-2 towers destroyed, 2-3 kills and the person I'm facing has been completely shut down and underfarmed. There has been few times where the jung would come up to gank and I would kill them both.

Than the team fighting starts. I ghost+ult in and quickly take out the enemy adc, turn around to go help my team and they're almost all dead. So I rush in and start hammering on any squishy I see. However by this time any of my team members that were still alive have turned tail and ran away and I'm now stuck in a 4v1 or 3v1.

I've tried staying back with the team when a team fight breaks out... that just goes even worse. I've tried split pushing thinking they would have to send at least 3 people to stop me sense there's a good chance I'll win most 2v1s, however when the enemy team sees I'm not there they usually dive and kill my team.

My build varies depending on who I'm facing or whoevers really fed. I usually try to build a lot of hp with 1-2 life steal items.

Any advice on where I might be going wrong or what I could do better would be appreciated.

Edit: I'm in bronze III