I spent nearly 8 years numb... I'm happy to feel lonely, happy to cry even when it's sad, happy to feel body image issues, happy to feel all the bad that happens...because it means I also can feel the good, the happies...it means I actually care!
I can feel happy, ... I like myself and I'm trying to love myself. But now, ...the foundation is there.
You can't cherry pick emotions ... you must take the good with the bad, its the contrast that defines them. What's important is your attitude, how you define your response to them.
When you're feeling down, do something nice for yourself. Put yourself out there and meet some peeps. But now you have the ability to truly enjoy their company when you do.
As for extreme mood swings, that's not normal and you may need to adjust your hormone levels. This is where trial and error and a good endo come in very handy.
I have a friend who is taking P, switched to injectable estradiol valerate 10mg q 1/52 ... and she has been a god damn emotional disaster since, but insists the problem is always something else... The problem is she was much more balanced and visibly happy before the P and while on E pills... So while it's great to feel, make sure you're not "artificially" over-stimulating emotions with "off" levels, find the level where your comfort is at, and it will take time. Cause from what I've seen (have many trans friends) it's pretty damn varied despite what the doctors may think. This is not a one size fits all (emotionally), sure it may feminize you but not be optimal for feels.
But to be blunt, it sounds more like an attitude problem than a level one. You really could use some healthy perspective on giving your emotions air time and how you respond to them. Face them with courage, don't be afraid to feel bad because and keep the hope .. there will be good, there IS good. Numb? ...there is nothing down that road and I think many of us have seen where it leads and hasten to change the topic.