A $0 balance could happen when a display delay is caused by the app needing to re-sync with all the services involved. Usually, when multiple services are involved in performing one operation (i.e., depositing into Strategies on AlphaLend from Slush), the Slush app requires a couple of minutes to reflect the balance accordingly. Mind that your funds are recorded safely on the blockchain, and the interface just needs a moment to catch up. If the balance is not reflected accordingly within a reasonable timeframe, within the app, a simple refresh on the Home screen usually resolves this.
Pull down on the Home screen to refresh and force a balance update if you are using Slush mobile, or refresh the current Slush instance when using Slush web, or the Chromium-based browser extension.