How do I get him interested again?

Just do nothing. If he's interested, he'll be in touch with you. If after a month you haven't heard anything, just drop by his house to pick up your stuff and accept that it is over. In the future, don't be needy, especially if you've slept with a guy before making him commit, he'll likely just move on and you'll be left in this situation again. Ease up on the sex before commitment and tone down on the communication if a guy isn't sharing in the back and the forth. If you follow these rules, you'll get yourself a boyfriend.

Yes you were needy and whatnot but if he really liked you there's really nothing you could do to "scare" him off. Guys that are really into you will chase you and won't stop communicating w you over something petty like you being too "needy". It's over just move on. Continuing to try and contact him after he's been ignoring you w the lame excuse that you left a hairclip, lipgloss, etc. at his place will just make you look even more needy and desperate. There's nothing you can do at this point but just get on w your life, forget about him, and meet other people. I mean you two were seeing each other for a few weeks it really wasn't anything serious. Those things you left at his house I would be willing to bet he's thrown in the trash at this point.

Just wait,because what damage you may have already done will be made worse if you say anything more when he has clearly ignored you.