Questions: Family & Friends

For some reason ever since I've been growing up a bit you know in those "areas" I've been feeling uncomfortable around my dad. He has never made any comments about my body but he has looked. This all started when i caught my dad looking at my breasts and legs while we were talking late at night in the kitchen. he's been a great father and i doubt he'll ever do anything to me or he even thinks of me like that but I don't know i did catch him looking at me and its been bothering me ever since. So much that I've been avoiding him. I wear baggy clothes around him or i just hide in my room or bathroom if he's in sight. My mom has been asking why im avoiding him and acting strange. I've actually started to hate him now. Im rude to him. he's seriously a great father but I don't know. Am i weird? Sometimes i think well what if he was just looking at what im wearing not my actual body and then i feel disgusted with MYSELF for even thinking of him having perverted thoughts about me. But something about him and being around him makes me feel uneasy and like sexualized. Maybe im going crazy and have issues but i swear i feel that something is going on. That maybe he does think of my body. I have big breasts for my age. He also makes commente about "spanking my butt" when im being rude and i know it sounds like just a father trying to discipline his kids but im already 16 and even my sister has made comments about how its pretty gross and wrong in a way. It does sound sexual for sure. I feel so bad , awkward and disgusted for even asking this but its been bugging me for so long , i need to talk to someone. Can someone please give me some feedback and advice? Am i just disgusting and delusional or do i have a reason to feel uncomfortable and disgusted around him?