iphone calendar info keeps disappearing
After synching my iphone yesterday almost all of my calendar info had disappeared. The info was still present in my google calendar online. After pressing the calendars button and confirming that "show all calendars" was chosen, my calendar info reappeared. Today while using my iphone calendar the info suddenly disappeared again. Pressing the calendars button didn't help this time, but after turning my phone off and back on, the info reappeared. I'm not sure how to prevent this and am afraid of continuing to rely on my iphone to keep all my work-related appointments. Any ideas?
iPhone 4