Be still. . . so that you can hear His whispering. Pray to the Holy Spirit for strength, enlightenment, guidance and consolation, and follow those little wiggles in your mind, that push you toward one activity or another and then follow them. See what organizations or activities are available in your parish and pray about them. Somewhere there is something that will spark that fire in you and then embrace it. And, remember that it may be for only a time and then you may be called to something else, or it may be for a very long time. God will reveal all to you in the proper time. And, that is the hard part -- that's why patience is a virtue :-). Focus on trying out what your talents might be and enjoy that learning experience. One of the hardest things to do, is to empty ourselves so God can fill us. Many, many human things keep us from surrendering to this, even when we believe we want it desperately.
And, if you find nothing in your parish, look at the diocese level or your community. God knows your talents, even the ones you don't think you have. I love the saying: God does not call the qualified, he qualifies the called. So, try out many things and always pray. Hugs.
I did get past the bitterness after a while. Mostly, I noticed it happens when I think only of myself. And so, I tried not to. It's not easy. Everyday I had to find a reason to be happy that I was single. Sometimes, the struggle to be happy is so ostensible that my face scrunches up with the effort to realign my thoughts. The miracle has been that up to now, I have found reasons to be happy that I am the way I am - from having all my time and money to myself, ease in travelling, time to serve others, freedom, etc. It's become a habit now whenever I start turning in to myself, that I consciously, purposefully count my blessings.
Yes, I still get sad and pensive from time to time. As happy as I can be, it's still easy to fall into that bitterness again. You just have to keep reminding yourself that God wants you to be happy. If He wants you to be where you are right now, then we just have to trust in Him. Look around, look at Him, instead of yourself.
And if that still doesn't help, just think that even Cameron Diaz - in all her blonde and long-leggedness - hasn't found her soul mate :) jk!