In addition, it is possible that the OP is confusing the "low lymphocytes" on the differential with an overall low total lymphocyte count. The differential does not give you the total number of lymphoctes, just the percentage of all white cells that are lymphocytes.
In bacterial infections, the proportion of neurotrophils will be higher than normal, meaning that the lymphocyte proportion is low. However, if the overall total white count is elevated, this lower lymphocyte proportion may reflect a normal total lymphocyte count.
So if a normal lymphocyte differential is 30% and a normal white count is 7000, the normal number of total lymphocytes is about 2100.
But if the total white count is elevated to 15,000 and you still have the same number of lymphocytes (because most of the extra white cells are neutrophils), then your lymphocyte differential will be low at about 15%, even though the actual number of lymphocytes is unchanged.