I need help!

Okay so me and my boyfriend have been together for 2 years and he always used to be so loving and would always spoil me and I absolutely loved it. There was never a time where he would drag to text me and he’d always answer my calls. Lately he has been taking longer to answer and sometimes sends my calls to voicemail. I’ve talked to him about it multiple times and how i get upset about it and he always says I’m sorry baby I love you and I promise I’ll start showing you more attention but then the same thing will happen the next week. He doesn’t show me off anymore. Didn’t do anything for me for my birthday and didn’t even say happy Valentine’s Day to me let alone actually buy me some flowers. What should I do? How should I handle it?