I listen to fan-made MLP and just MLP music ALL THE TIME. I love WoodenToaster and TheLivingTombstone and there's loads others. Just try out listening to the music and see what you like. I make lots of fan art (I'm drawing ponies right now!) and ship ponies too. Read fan-fictions about whatever pony or coupling or anything you want. The MLP fandom produces so many great things to help last you to you the summer! And of course post on this forum as another pony thing to do!
And there's non-pony stuff you can do too. It's kinda wierd for me, 'cause I know that I listened to music and had tons of hobbies before a became a brony. But then I'm like "what DID I listen to?". But there ARE so many things you can do. Video games, draw, read, daydream, do activites with friends and family, do outdoor sports, etc. Also, there are fun stuff going on in this world other than ponies to look forward to. And not just new TV shows, but like, for instance, there was a Venus transit over the sun today. It ain't gonna happen again 'till 2117 or something. I'm interested in astronomy, so I had that to look forward to. So stuff like that.