Breast feeding fail!!!!

So I really wanted to breast feed my baby this time around. My supply was real low and since I was pumping it was hard to keep up with her feeding demands as I could only pump about 4oz at a time if I was lucky. Eventually my milk dryed up even though I pumped often. Even tho she hasn't had breast milk for about 2 months now (she is 3 months old) I always feel so guilty I wasn't able to provide her with my milk. I've been told I can re establish my milk supply but with me going back to work and all of my medical issues I don't think I'll be able to. I just feel so awful. Is there any moms out there who had similar issues? Anyone have any advice on how I can get past this? Is it worth it to try and get some milk back and even just supplement with breast milk? I just feel so alone I feel like a failure as a mother!