There are several reasons for swollen feet - they include heart conditions (cardiomyopathy), any type of renal dysfunction, or liver dysfunction. To work this up, I would suggest liver function tests and albumin (a type of protein) level, an echocardiogram, and kindey function tests (a creatinine level).
If every test is negative, you may just want to treat the symptoms with a water pill as some people are just more prone to retain water.
Regarding the night sweats - again, there are a myriad of causes. From your question, you are negative for TB. I would go through any medication that can be causing this, as well as test your thyroid as well as an HIV test. There are a variety of cancers (i.e. lymphomas) that can cause night sweats. You may want to discuss with your personal physician a chest and abdomen CT scan which is a reasonable first step to evaluate for this.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
have you been checked for diabetes and thyroid?