welcome to the forum, republic5. i'm so glad you found us. lots of good support here and know that i had similar challenges when i first got sober. it's called a "rollercoaster" of emotions. you sound honest and with a good head on your shoulders. i too congratulate you on your 59 days sober. each day is another miracle for all of us. might i suggest something? speak with your sponsor. he may have some suggestions for you during these days. many of us felt depression and loneliness at first. not comfortable in your/our own skin. as you gain a good foundation in AA this will lift. you are beginning a new way of living. an incredible gift to yourself.
as for your former girlfriend. it's highly probable she felt she lost her "drinking partner". your sobriety made her nervous cause it reminded her she might have a problem too and she didn't want to look at that. it sounds like right now you feel the void of her leaving. i can assure you that void will be filled with lots of wonderful things. it's a side benefit of sobriety.
my sponsor told me many years ago this:
"j___,you didn't get sick overnight and you won't get well overnight". but the good news is if you stay sober your spirit will heal. your hope will return. your belief that you can make it is strengthened every day you're sober.
each day pick a quiet time to read parts of the Big Book. read the "Promises" for they will come true is we stay sober. for me it was beyond my wildest dreams.... a time to reflect. a time to look forward. a time to see the miracle of your sobriety. doesn't have to be a long period of time each day but you will benefit from this exercise. if your mind wanders acknowledge it then focus back on your quiet time.