Tory MPs and even allegedly ministers are plotting her downfall and the scrapping of her withdrawal agreement.
It comes after she told Sky News' Sophy Ridge on Sunday that the next seven days would be "critical" to achieving a successful Brexit.
Here's what to expect from the next week:
Mrs May's internal party opponents need to convince 48 MPs, 15 per cent of the parliamentary party, to send letters of no confidence to 1922 backbench Committee chairman Sir Graham Brady to force a vote on her leadership.
He has either received them, is close to receiving them, or is nowhere near close to receiving them, depending on who you believe.
Only Sir Graham knows for sure and he has not even confided in his own wife.
No. If there is a confidence vote and if Mrs May does not win it the subsequent leadership election, which she could not contest, would take up to 12 weeks to run.
A group of cabinet ministers who declined to follow Brexit secretary Dominic Raab and work and pensions secretary Esther McVey out of government in protest last week are said to be conspiring to force the prime minister to seek last minute changes to her withdrawal agreement.
Given it has taken two years to hammer out an agreement and that the EU has said it is their final offer, their delayed departures could be more likely.
That could alter the timing and quantity of any no confidence letters hurtling towards Sir Graham's office.
The cabinet cleared the way for the special Brexit summit in Brussels on Sunday when it, reluctantly in places, gave the green light to Britain's Brexit blueprint.
The November 25 event will see leaders of the remaining 27 EU states asked to put their stamp on the document. The agreement will then be sent for ratification to both Westminster and the European Parliament.
Before the November summit date, an agreement will also have to be reached on the political declaration, published on Wednesday, on future relations - which is currently an outline and due to become a full future framework.
Mrs May revealed that she is to visit Brussels this week for talks with senior figures including Jean-Claude Juncker, the president of the European Commission.
Ministers from the EU27 ministers will meet for the General Affairs Council in Brussels on Monday to discuss the draft Brexit agreement.
Closer to home
Mrs May will chair a meeting of her new look cabinet on Tuesday, the first to be held after the departures of Dominic Raab and Esther McVey.
It will be a welcome back for new department of work and pensions boss Amber Rudd and Stephen Barclay, who steps into the Brexit firing line - albeit in a reduced, domestic capacity.
Sparks could fly
Mrs May will face Prime Minister's Questions on Wednesday. It could mean some tough questions from both the opposition and within her own ranks.
Additional reporting by Press Association