Finding money

I was cleaning out a closet in our house, and I found a suitcase completely packed with cash. I confronted my husband about it and he told me it's money he's saving for a down payment on a house for us. I feel like he's hiding money from me. We haven't spoken since last night. I feel betrayed in a way, like he doesn't fully trust me. Am I making a big deal out of nothing? Is this just pregnancy hormones talking (I'm 8 months)?