HELP!!! Keep losing items, really need your help...?

I'm in an after-school sport [school]year-round, so I usually bring a waterbottle. My mom bought me a nice gray Nalgene one, and I lost it at an away basketball game. I also lost a PAIR OF JEANS (don't ask how, I don't even know) at an away bball game. Just this week I've started track and 2 days ago I LOST MY NEW NALGENE WATERBOTTLE that I bought myself this time. It's so inconveinent and expensive (being in middle school and on the go go go), so what are some healthy habits I can start getting into to KEEP TRACK of my stuff? I'm so desperate and I haven't told my mom yet about the green WB I lost. I'm disappointed in me, and I'm sure she will be too. I'm looking high and low. but still no luck. PLEASE HELP!!! :-(