IPN Notification URL for paypal single payment

I've been up all night, trying to make my website ready for launch by morning (it is 3:40am here now).

Right now, when you pay on paypal, nothing happens. Paypal takes your money, but you don't get a subscription. None of the transactions show up in my transaction history in wordpress.

I have enabled IPN in my paypal account. I could not enable it without adding a URL. What URL am I supposed to use? Why is there no documentation on this? I am extremely frustrated.

I have tried the paypal express gateway using this as my notification URL: http://thenormalschool.com/paymentreturn/paypalexpress

I have tried the paypal single payments with this as my notification URL: http://thenormalschool.com/paymentreturn/paypalsolo.

Nothing works. If I look in my IPN history, all of the transactions just say retrying. Please, please, please, help me.