I need advice about my relationship with my ex-g/f of 5 years who I have a son with....?

I am 22. I have been with my g/f, or ex now, for the past 5 years. We broke up 3-4 days ago. We have a 2-year old son together. We met in HS, and were very close. We always did things together, like going to the movies, mini-golfing, shopping, dinner, six flags great america, stuff like that..When we had our son, things obviously were stressful. It wasn't a planned thing to happen, and we dealt with it the best we could. Now I wouldn't say we fell apart once our son was born, but we stopped doing things as a couple. I understood that was going to happen initially, b/c we would have less time together. We have been living under my mothers roof the past 2 years, trying our best to get ourselves on our feet. I havn't had a steady job since July 2008. I have still made 30-35K per year doing odd n end type of things (ebay, buying/selling electronics gift card, small end jobs, etc). I made that much while watching our son every single day for 2 years. She worked full time at $8.50 an hour. I never complained b/c she did her best, and I was proud of her since it was her first job. About a month ago, she got promoted to a manager position at her department store. She got higher pay and benefits. I was so happy for her, my mother was stoked, bought her a cake, etc..Then about two weeks ago, I caught her talking to her boss on Facebook chat, talking all ual and lovey dovey. She left her Facebook open downstairs on the PC, while she was talking to him upstairs on my laptop. I sat there for 20 mins watching it all go down. I confronted, and obviously I was angry, hurt, emotional, etc. I still wanted to work things out for my sons sake. I love her, even though what she did to me. Then about 3 days ago, she dumps me. She says she doesn't have feelings for me anymore. I am a smart guy and I realize having a kid at such a young age with no future set for ourselves wasn't the best idea. My son is my life though, and I feel like **** everyday knowing I won't see him like I used to. I went from watching him every single day, taking him to the park, changing his diaper, giving him baths, etc...to seeing him maybe 2-3 times a week. I was and still will be a dedicated father. I was ALWAYS here for him, and always will be. I am just hurt by this ordeal. I did my best as a father, to watch him everyday, and still make 3 times the income my ex was bringing in. I never once complained and I dealt with the struggles of having a son so early in life the best I could. I still love my girl and I'm feeling like complete ****. I didn't do anything wrong throughout the relationship. Never cheated. I always tried to make her happy before myself. 5 years is a long time, and I do understand that this happens all the time in life. But since I am so young, and a mother who is a die-hard christian, I need advice elsewhere. She just tells me to go to church and pray, lol...I need some advice to get on with this. I still have crazy feelings for my girl and I still envision us being together. I don't call/text her every min stalking her, I am not like that. I am not acting desperate. I just need ways to cope. I've been riding my bike for 15 miles a day, listening to music, making slideshow videos of my son, etc...And BTW, I have been going to 3-4 interviews a day, now that I have time during the day. I did my best for my family given the cirstances. I am in tears now. Men DO cry.