Chronic diarrhoea with salmonella is a risky combination. Reversal of N:L ratio in this can be a sign chronic infection. Salmonella for more than 4 weeks and cause AKI and TID, in that situation epithelial cells can be found on urine routine examination. Raised ESR and thrombocytopenia can be secondary to ongoing inflammatory reaction.
Next Steps
Since things can complicate further, the most dangerous being bowel perfortaion, I'd suggest to get admitted and rehydration acc to fluid deficit protocols. Get complete blood
electrolytes checked, abdominal imaging may be required. Antibiotics should be stepped up. I'll personally recomment parenteral Ceftriaxone with Azithromycin combination.