Idioms:

1-on a knife-edge in a difficult or worrying situation of which the result is very uncertain: if a person or organization is on a knife-edge, they are in a difficult situation and are worried about what will happen in the future
At the moment the election seems balanced on a knife-edge.
She's been living on a knife-edge since her ex-husband was released from prison last month.
The theatre is on a financial knife-edge and must sell 75% of its seats every night to survive.

2-be a drag on sb/sth INFORMAL
to slow down or limit the development of someone or something: a person or thing that is a drag on someone makes it hard for them to make progress toward what they want:
• Maggie thinks marriage would be a drag on her career.
She didn't want a husband who would be a drag on her career.

3-to get off one’s chest
get something off your chest: to tell someone about something that has been worrying or annoying you for a long time, so that you feel better afterward:
• People are able to get things off their chest in these meetings.
get off my back! INFORMAL
used to tell someone to stop criticizing you:
Why don't you get off my back! I'm doing my best.

4-to take an one's words
take sb at their word

to decide to believe exactly what someone tells you, even if it does not seem likely to be true
When he said he'd give me a job, I took him at his word and turned up the next day at his office.
If she says she's sick, you have to take her word for it (= believe her).
take my word for it SPOKEN used to say that someone should accept what you say as true:
• Take my word for it - she's really funny.
5- what is life in the fast lane
the fast lane
a) an exciting way of living that involves dangerous or expensive activities:
• McCravey lived his life in the fast lane for 27 years.
b) the part of a large road, especially a HIGHWAY, that is used by fast vehicles
life in the fast lane
a way of living which is full of excitement, activity and often danger:
Parties, drugs, and a stream of glamorous women - his was a life in the fast lane.
fast lane noun [S]
the part of a main road, such as a motorway, where vehicles travel at the fastest speed
6- play second fiddle to sb.
if you play second fiddle to someone, they are in a stronger position or are more important than you; to be less important or in a weaker position than someone else: to be slightly lower in rank or less important than someone or something else:
• He was never more than a B-movie actor, playing second fiddle to actors like Errol Flynn.
You'll have to choose between your wife and me. I won't play second fiddle to anyone. [usually + to]
I'm not prepared to play second fiddle to Christina any more - I'm looking for another job!
7- walk on air
to feel extremely excited or happy: to feel extremely happy:
• On my first day, I earned $190, and I was walking on air.
After the delivery of her baby, she was walking on air.