My alarm sound decreases to virtually nothing when it senses that I picked up my phone. How do I stop this from doing it automatically?

My alarm sound decreases to virtually nothing when it senses that I picked up my phone. How do I stop this from doing it automatically? Once I pick up phone, Apple senses I'm awake and it decides I'm already awake and I don't need the alarm.

However, this is becoming a problem. How do I stop it from doing this automatically?