Hi thanks for your question .
Most probably your suffering from urinary tract infection
(UTI) along with enteritis
(infection of intestine).Disodium hydrogen citrate is an alkalizer which increases the urinary PH and decreases burning sensation.
There are many antibiotic which are safe in pregnancy
Get your urine examination done to confirm UTI.
You may need consultation with your gynaecologist,who may prescribe you antibiotic for UTI as well as for entritis.
Hope this answers your question.