Soo,too either and neither

Positive Statements

1. Using 'So'

Grammar: So + auxiliary/modal verb + pronoun

Note:
We should pay attention to the verb tense used in the statement while choosing our auxiliary form.

Speaker A’s Statement	Speaker B
Joe  is watching TV.	So am I.
Sam can speak english fluently.	So can I.
Terry has completed his master’s degree.	So has James.
His parents should be more responsible.	So should we.
Stephanie was so worried yesterday.	So was I.
Mary and Sam will join the chess club.	So will Jessica.
Nathan looks so confident.	So do I.

2. Using 'Too'

Grammar: Pronoun + auxiliary/modal verb + Too

Speaker A’s Statement	Speaker B
Celine is watching TV.	I am too.
Sam can speak French fluently.	I can too
Terry has completed his master’s degree.	James has too.
His parents should be more responsible.	We should too
Stephanie was so worried yesterday.	I was too
Mary and Sam will join the chess club.	Jessica will too
Nathan looks so confident.	I do too.

In Negative Statements

1. Using 'Neither / Nor'

Grammar: Neither (nor) + auxiliary/modal verb + pronoun

Speaker A’s Statement	Speaker B
Maria  isn't sleeping.	Neither (nor) am I.
Gloria cannot play the drum.	Neither (nor) can I.
Rey hasn't eaten her egg.	Neither (nor) has Ran.
They shouldn't complain.	Neither (nor) should we.
Rani was not worried at all.	Neither (nor) was her husband.
Marca and james won't attend the meeting.	Neither (nor) will I.
Cat  cannot fly.	Neither (nor) can dogs.

Note:
Although there is a negative statement, we use a positive auxiliary form. Speaker A: He isn't guilty. Speaker B: Nor is Tom. (Not Nor isn't Tom.)

2. Using 'Either'

Grammar: Pronoun + auxiliary/modal verb + Either

Speaker A’s Statement	Speaker B
Maria  isn't sleeping.	I am not either.
Sandra cannot play the Drum.	I can't either.
Jennifer hasn't eaten her egg.	James hasn't either.
They shouldn't complain.	We shouldn't either.
Rani was not worried at all.	Her husband wasn't either.
Marca and james won't attend the meeting.	I will not either.
Cats  cannot fly.	Dogs  can't either.

In Informal Interactions

When speaking or in less formal writings, regardless of tense, we can use “me too” and “me neither” in firt person.

All the following examples are acceptable

A: I have been studying a lot recently.
B: Me too.

A: He never attended the class regularly.
B: Me neither.

A: I haven't been feeling very well.
B: Me neither.

Source : https://www.grammarbank.com/so-neither-either-too.html