Help calculating P&L Daily/Weekly

I’m using the c# sdk trying to determine how to come up with a way to calculate P&L from previous days. Currently i have the example below to get the current P&L for that day, but I was hoping there was a way to query previous days or roll up weeks? Any help is appreciated…

//Current Day Only
var account = await alpacaTradingClient.GetAccountAsync();
var balance_change = account.Equity - account.LastEquity;