Basically eBay have moved you across to their Managed Payments system that they have started to roll out recently. Although some sellers are still using the old system, in which case the money they make from their sales will go straight into their PayPal account, eBay intend to move all sellers across to the Managed Payments system eventually, but so far it would appear that they are moving business sellers over to eBay Manged Payments first of all, with private sellers set to be switched over at some point in the future.
Unfortunately it would appear that there have been some teething problems with eBay's Managed Payments system, as there have been reports of payments taking up to a week to clear into the seller's bank account, whereas with the old system the money would transfer across from the buyer's PayPal account and straight into the seller's PayPal account as soon as the buyer clicked on the button to make payment. As ever, eBay seem to be making a complete and utter pig's ear of every "improvement" to the site that they make, so I can only see things getting a hell of a lot worse before they even start to begin getting better.
Although I can't see how eBay are going to make this Managed Payments system better than the old system that they're hellbent on getting rid of, if you want the funds to go into your PayPal account the only way of doing so that I can think of at the moment would be to transfer some money from your bank account and into your PayPal account so that you could use your PayPal balance to fund any purchases that you decide to make using your eBay account.
Should eBay decide to completely do away with PayPal and introduce a payment system that removes any need for buyers to pay for purchases using PayPal then it will make PayPal completely obsolete with regards to buying and selling on eBay, and given that eBay seem to have an annoying habit of ruining everything that they try to improve about this site I really can't see this being a change for the better. I suspect that eBay will lose a lot of buyers and sellers in the long run, as there have been quite a few complaints on the forums from buyers having problems making payment for items that they want to purchase, as well as sellers who are not happy with the switch to Managed Payments.
PayPal is no longer an option for you. Not sure where you've been, but over the last year or so you will have received countless emails and mesages from Ebay preparing you for the switch from PayPal to Managed Payments.