YY - my DM said this when I was pregnant with DCs 2, 3 & 4, and everytime DH went away on business..."How will you cope?"
Basically daily life is a struggle for my DM, so she assumes that everyone else is an inept at coping as she is. Your DM's reaction says more about her than it does about you, OP.
My response to the coping question, in all it's forms was "Well where will not coping get me, Mum?"
If I decide not to cope, how's that going to work, exactly?
It's as annoying as hell, witsender, so you have my sympathy. And yes, my DM quite liked the idea of me not coping, I suspect because it would have made her feel better about her own inability to cope, and because she would have felt needed, which she loves & hates all at the same time.
Best of British to you. You will be fabulous!