from the description ,it seems you are having some thing that resulting in low grade temp and increased pulse rate.
as the relevant blood tests are not showing any abnormalities ,may be it is just the convalescence . do not worry and have healthy diets with enough calories.
plenty liquids to be taken so that there is no dehydration
that may give rise to low grade temp and increased pulse rate also ,
In case you have persistent complains please get a check up again with your doctor and discuss it for any further investigations
U S G exam of whole abdomen if not already done may be helpful.
wishing your early recovery