English grammar has been confusing me for a long time, so I want to ask some questions about the past and how you use it. I'm more interested in information about British English.
When and how do you use, for example:
haven't felt,
hadn't felt,
felt,
wasn't feeling,
has been feeling,
used to feel.
and what's the difference between them?
I kind of understand the difference, but not sure if I do it correctly.