I’m in a hurry

When you are in a hurry, you are not able to wait to do something because you do not have enough time.

• I can’t wait. I’m in a hurry to get there.

When you are not in a hurry, you either have plenty of time on hands or are unwilling to do something.

• I’m in no hurry to get married.
• Let’s discuss your plans. I’m in no hurry to leave.

I’ve got to go now

‘I’ve got to go now’ is something we often say when we are late for a meeting or engagement and wish to depart from present company.

• I’ve a meeting at 4. I’ve got to go now.’

The expressions I gotta go and I’ve gotta go also mean the same. They are mainly used in colloquial English. Note that got to is pronounced gotta in informal American English.