I guess my main problem is that I feel as if I have no right to feel the things I do. I've had this amazing woman there right next to me the entire time(who has also been warning me for 3 years about how my connection with J would only lead to more pain and grief)...and she is so empathetic that when i do turn to her to tell her how upset I am that she also gets upset
You feel what you feel when you feel it. Rain is rain. Sun is sun. Grief is grief.
When you lost your father, did you not have the "right" to feel that for his loss? Or did you have to apologize to your coworkers for that? The postman? The grocery clerk?
C'mon. Cut yourself some slack here. Emotions is just internal weather. Let it blow on through. Feelings have to be expressed or you get clogged up.
As for M, I'm sure she is doing all she can. But if you grief is 100 gallons, and she's a 5 gallon bucket -- even if she takes 100% of her ability? You are overloading her. Spread it around. If you need extra support -- see a counselor. Talk to other friends about it rather than NOT wanting to talk about it. See if there is a class -- two friends of mine both wen thru divorce at a bout the same time and they went to a divroce support group class thing for a few weeks to help them bear the process. Write in a paper journal. Open a blog thread here. If you are religious, see your religious leader for a pastoral care appointment. Call a hotline. Steam valve in appropriate ways.
Burdens shared are lessened. Joys shared are increased. It takes a village. You know what I mean?
Hang in there.