Hey Sharon If the app doesn't recognise you. When you open the App, click the menu icon on the top Left corner to open the menu.
Then click on the "Account" text and NOT the little cog next to it. This should log you back in again. It does this to me from time to time as well so you not alone. But clicking on the account text quickly logs me back in.
To know if you are logged in or not, when you have selected for "Forums" menu option, click at the top of the page which says "by category" and if it shows the "Participated" option, then you are logged in. Hope that makes sense haha.