Adblock Plus

For about a week or two, I have been reporting to ABP that ads were appearing on especially Lexulous (a game like Scrabble) and on The New York Times site. Yesterday the icon is no longer on my Firefox top-line menu. I have rebooted the computer. I have deactivated and reactivated ABP. I have re-downloaded and reinstalled the add-on. If I go to a site that needs to be whitelisted, it shows I have an adblocker on, but I cannot access ABP without the icon. ABP is activated on the Firefox Tools>Add-Ons list.

ABP version 3.1
Firefox 78.5.0esr
iOS 10.11.6

It works in Safari and Chrome, but not Firefox. What else can I do to get Adblock Plus back working, please?

Right click the toolbar. Left click customise and if the icon appears in this overflow space drag it to the toolbar

Thank you. It turns out the icon automagically reappeared, and all is well. But, again, thanks for your good advice.