Is my faith lacking?

Assalamu alaikum, I was born into a Muslim family but only started practicing seriously later in life. I really want to be a good Muslim and I'm trying my best. I used to pray all five salah and dress modestly with hijab. Lately though, I feel like my heart isn't fully in it. I have so many doubts. Even when I stand for prayer, it feels more like a routine task than an act of iman. Please guide me – am I a bad Muslim for feeling this way?