Usually when problems are so complex, it takes some time (meetings, study, etc.) to make some headway in discovering what actions are right for us.  And I know that feeling of "The old ways didn't work so well, but what are the new ways?" 

One thing that was very helpful to me when I was starting to figure things out was to read about family dynamics and what they call "family systems theory."  It just means that things happen in a dynamic, not just one person at a time.  (It sounds obvious now, but it was a revelation to me then.) 

I also know that I was at sea about what was right and what was inadvisable.  So I'll comment a little about what I found out, with the proviso that of course you are the only one who knows your situation well.

My first reaction when I figured out how dysfunctional my mother was, was to cut her off.  We had an intense relationship, full of blame (some of it justified), anger, unfulfilled expectations, and pain.  But I read in these books that cutting someone off is just another version of intensity.  It escalates the anger, pain, blame, etc.  And I looked back and saw that in my family, there were all kinds of instances of people cutting off other sides of the family.  It was our family way of dealing with anger.  But it just led to more intensity somewhere down the line.  (I am laughing as I'm writing this, because I'm writing from a family member's house that cut us off many years ago, and then we cut them off ... etc. etc. ... but then I got back in touch years ago and right now I'm a happy guest here!  If that isn't a reward for me, I don't know what is, and I hadn't thought of it that way, so thanks! )

Instead this way of thought suggests that we de-escalate the intensity by learning subtler skills, such as not taking the bait, setting loving boundaries, cultivating our own serenity -- the skills that Al-Anon helps us with anyway.

I can see that your father's demands may well have some controlling features in them -- "Answer me right now or else!"  Also it is natural for him to be worried about a daughter.  I think maybe in your shoes I'd say, "I'm here, Father, and I'm fine, don't worry if you don't hear from me much for a while -- I'm taking some time to get clear about some things, but thanks for checking on me, no worries!"  Of course he may well then launch into a big tirade about your faults, but as my therapist used to say, "So many chances to practice your health behavior!"  Like, "this is hard for me to hear, so I'm going to sign off now, talk to ya later, bye." 

If he is contributing to your support, also, I think that means that you have to keep in touch, don't you?  But there are new ways to deal with controlling, blaming people.  They're not learned overnight but they're there and they're powerful.  I hope you'll keep coming back.