seeking guidance: i truly want to come back to Allah

Assalamu alaikum. Please don't look down on me. I never imagined I'd open up like this, but I'm in desperate need of advice and have no one I feel safe talking to. I feel like I've been a terrible daughter. I don't pray, and I've neglected Islam for a long time. Growing up, I mostly practiced out of fear of my parents. I'd wear hijab in front of them but sometimes take it off when they weren't looking. Over time, I drifted further away. Now my father is unwell-dealing with diabetes, high blood pressure, and lung issues. I love him dearly and want him to heal. I also blame myself, thinking the stress I caused might have worsened his health. He keeps telling me he forgives me, but I can't forgive myself. Something in my soul is pulling me back to Allah. But then a voice whispers, "You're only doing this because your father is sick." It feels odd to suddenly turn to Allah now, when I wasn't praying or taking faith seriously before. I'm scared my intentions are selfish-that I'm just reaching out so Allah heals my father. I've read online that Allah is forgiving and that I should simply return, but I still don't know what to actually do. I keep searching, but nothing seems to click. I feel lost, guilty, and overwhelmed. I don't have anyone I can safely vent to. The religious people I know are close to my family, and I'm afraid of being judged or made an example of. That fear kept me from seeking help. Also, please understand, I'm on my period right now, so I can't even start with salah. I genuinely don't know what's allowed or where to begin. Can I sincerely return to Allah if my father's sickness is the reason? What can I do during these days? How do I make tawbah when I'm overwhelmed and don't know where to start? And how can I ask Allah to heal my father without feeling like I'm only turning to religion out of fear? Please be honest. I really want to come back.