There's a confidence motion tomorrow evening at 7PM GMT. My understanding is, if the government loses a general election is triggered which takes a couple of months. So a new government could be in place before March 29th. However, I think if a general election was to happen then all sides would agree to ask for an extension to Article 50 and allow a few extra months for the new government to decide what to do. Another caveat to that: one manifest pledge in the election may be a 2nd referendum. If that party won then the 2nd ref would become the focus.