37 year old - just diagnosed

My scenario is similar to yours, except I was 3 years older than you when diagnosed and my cancer was grade 3, multifocal with lymph node involvement.  I said to the BC nurse that I was worried about putting on weight.  She told me not to worry and said I’d probably lose weight.  She was wrong - I put on 8 kilos (most of this weight gain was during taxol and I put on 500gms a week over 12 weeks).
Everyone reacts differently.  We all got through it.  I think being younger has its advantages.