"i am taking phentermine 37.5, usually taking a full pill, but sometimes only taking half because of the way it makes me feel especially at night.  i have a hard time sleeping and have my heart pounds.  hoping these side effects will go away but it has been a little less than a month and i still experience them.  i have already lost 22 lbs and hoping to lose the rest in another 2 months because my doctor said i can only take it for 3 months...if i keep losing like i have the first month i will make it.  i just wish i wasn&#039;t experiencing these side effects because sometimes they are really hard to deal with."