Taking oath of allegiance to US government makes one lose Filipino citizenship

Dear PAO,

I was born and raised in the Philippines and my parents are both Filipinos. When I was about 25 years old, I went to the United States to work. After 15 years, I was granted US citizenship. I learned that being a US passport holder, I can only stay in the Philippines for a certain period of time. Should I be treated like other foreigners who do not have Filipino blood? My parents and all my siblings are still Filipinos and I own land in the Philippines.