Yes. You can hold open positions over weekends and holidays (GTC §8.3).
While the market is closed, you cannot close or modify any position. Any change can only be made while the market is open.
Watch out for gaps: when the market reopens, the price may open far from where it closed. If your equity goes past the daily loss limit or the maximum loss at that open, the account breaches the limit, even with a Stop Loss, because the order is filled at the first available price. Slippage is not reversed (GTC §8.3).