First, So sorry to hear about your Dad. Seeing a family member in that state can't be easy. As far as your sister goes...Darn, what is she thinking moving away from you? Doesn't she know how good she's got it living close by ?
Now, 'bout them setbacks. Nobody said you were free and clear now. The progress do date is not going to make all future setbacks disappear, sorry, but that ain't how it works. BUT, I think you will find that as you two grow closer and learn how to communicate better, that your periods of disillusionment will become shorter, less frequent, and perhaps less intense. They'll never go completely away, that bliss is reserved for heaven. Keep the discussions loving, but don't hold stuff inside...it will only build resentment. Let him know in a loving way that you are feeling neglected, that you understand that it is a stressful time, and that by remembering to nurture your R will help to alleviate the stress all around. You've done tremendously over the last 3 months or so. This isn't a trainwreck, it is just a stop-light along the way, so don't go overboard trying to fix/prevent it. I know you'll work through this, but do try to get rid of that TSBOR. Cut huge holes in the bottom of it and throw it away. There is no need for a bag-o-resentment, no matter how small (and certainly not Texas-sized), in your R.
Oh, and remind MrHP that it isn't you getting off that is important, that what's important is that ML is what makes you feel loved, and that you are currently feeling a bit neglected. Don't forget to keep trying to feel what he's feeling too, it isn't all about you, it is about both of you and your R.
You'll pull through this, I have faith in you. BTW, have you signed up for WWME yet?