Was I Wrong to Turn Down My Cousin’s Proposal When My Heart Wasn't at Ease?

Assalamu alaikum. I recently said no to a marriage proposal from my first cousin. We grew up like siblings, and to everyone else it seemed like a safe, familiar match - something that would keep our families close and maybe make life easier for my mother. But my heart just couldn’t accept it. It felt more like a marriage of convenience than one where I could feel peace. I prayed istikhara, but instead of calm I felt uneasy and suffocated. Logically it made sense, but emotionally I couldn’t find rest. Now that he’s getting married to someone else, I keep asking myself if I made a mistake. Sometimes I wonder if I should have accepted what I already had in the family instead of hoping for something from a stranger. Is it wrong that, even with familiarity, safety, and family support, I still felt uneasy? It makes me feel selfish and ungrateful. I wanted peace and happiness for myself and for my mother. Maybe she could have had that stability if I had said yes. I’m scared I might have turned away from something good and that I won’t be blessed like that again. With so many sisters struggling and so many marriages failing, I can’t help but wonder if I let go of something I was meant to keep. Was it wrong to reject someone who seemed good just because my heart couldn’t find peace? Lately my iman has been low. My heart feels heavy and distant from Allah, and I don’t even know what to ask for. I want peace, forgiveness, and clarity, but I feel lost. Please make dua for me that Allah guides me, heals my heart, strengthens my faith, and grants me what is best. What duas or practices can help me accept Allah’s decree and find comfort? I also fear my family might resent me for this decision in the future - I ask Allah I’m not tested or humiliated, and that He writes something better for me. I don’t mean to sound selfish; I’ve always prayed sincerely for ease for my family and myself, not to harm anyone. Jazakum Allahu khayran for any advice or duas.