I feel so sad and like a failure 😭

My baby is 7 months and she is my only one I always said I wanted to breast feed .I been doing it so good but now I feel like I'm not producing enough milk my supply is not much now when I put at work is not much only 4 -7 oz is not like before that I use to pump even 12 oz .

I feel like a failure because I feel like it my fault idk what I'm doing wrong. When I come home she is quickly wants breast and I feed her . I leave to work at 5 am in the morning and I come home at 3 pm .

I really want to feed her at least until 1 year old but I get is not happening.😭😭😭😭😭