I feel like all the happiness I have felt these weeks was fake

The moment my favorite person's tone shifted and he has been texting me way less than before I started getting the anxious and hollow feelings I used to have before meeting him,

He met my emotional needs which grounded me for months and calmed the demons inside me but now I feel like I'm losing him and suddenly all the persona I built about my self esteem shifted I now feel like I'm unlovable and unworthy, I have been seeking attention from people to feel some kind of validation at least