With your description it only means that you have fluid retention in extravascular (that is out side the vessels though which blood flow) space to this are added symptom of weight gain and shortness of breath. I would consult a doctor for there are three clinical conditions which have to be excluded
1. Congestive Heart Failure
. Systemic venous congestion
. Not being able to relieve during the time when you lie down and feet are up, absence of any knowledge of heart disease
in an educated adult and absence of aggravation of symptoms during sleep waking you up are pointers against it.
2. Renal, Nephrotic Syndrome
like condition. A urine test for protein and microscopy combined with blood tests will exclude this.
Your doctor will like to consider and exclude Hypothyroidism
, Diabetes and liver disease. That should be possible with clinical examination and some simple blood tests.
There is no cause for worry but definitely cause for concern.
With best wishes
Dr Anil Grover