The phrase "constantly nagging" is correct and usable in written English.
You can use it when referring to someone who is persistently "nagging", which is a term for speaking persistently or continually about a subject, often in a complaining or critical way. For example: My boss was constantly nagging me about meeting deadlines.
If you really have a strong feeling that someone is watching you that just won't go away, constantly nagging you, then don't just stand around because that nagging feeling may be trying to save you.
She cursed him for being "a bloody big 'ead" and was constantly nagging him to "shift yer bloody books".
Our kids are constantly nagging us for access — more time for playing games, doing homework, catching up with friends or watching endless hours of YouTube.
This car is like an overprotective parent, constantly nagging for fear that you are about to do some damage to its white paintwork.
Smart gadgets are the natural allies of such schemes: they document the results and can even help achieve them – by constantly nagging us to do what's expected.
I mean, the voice in your head when you're writing philosophy for philosophers is constantly nagging you to clarify and make distinctions and giving you lists of objections that you need to address.
They may feel they have no choice but to constantly nag to make sure things get done.
Reflections by a radio continuity writer; trying to keep his mind on his work, but constantly nagged by thoughts of his debts.
Chicken rice may serve as the national dish, but bak kut teh, literally pork-rib tea, was a dish about which I was constantly nagged.
In the novel, Krishna, the protagonist, is, like earlier Narayan heroes, unhappy with his place in the world, "constantly nagged by the feeling that [he] was doing the wrong work".
By Irwin Shaw The New Yorker, August 5, 1939 P. 15 Reflections by a radio continuity writer; trying to keep his mind on his work, but constantly nagged by thoughts of his debts.
