hi guys,
so i live with health anxiety and cardiac anxiety and i check my blood pressure usually every day 3/4 times a day and its usually elevated but when im not stressed as much its now sitting at 120/60 and sometimes 120/55 and im scared the diastolic is too low and im worrying about it a lot. im only 17 fairly active slim and healthy no medical issues or nothing all clear. Is my diastolic fine ???
most doctors don’t worry about slightly low blood pressure unless it’s causing symptoms. some of those symptoms include dizziness, fainting, falling, blurred vision, extreme tiredness.
Your diastolic blood pressure is not dangerously low.
sometimes if doctors want somebody’s blood pressure to be a little higher, they would suggest using more salt in the food, and drinking more water. but then you don’t want it to go to high either.
as a general guide, the ideal blood pressure for healthy young adult is between 90/60 and 120/80. Better to be on the low side than the high side. But you’re reading of 55 diastolic is nothing to panic about. you don’t have to check your blood pressure three or four times a day.
Just let your doctor know if you get those symptoms.
Your blood pressure won’t fall so low that you would be in serious trouble unless you have some underlying condition that could cause that. in other words it won’t naturally just dropped really really low unless you were bleeding or had some kind of other major health condition.
but in general low blood pressure can be easily fixed. You’re OK. Nothing to panic about. Take your pressure once a day . then get on with your life.! 
I had to recently give blood pressure readings to my doctor over a 7 days basis. i took it twice a day and sent the readings through. my pressure was up and down but from what the doctor told me they take the average over the period provided. Also like you I had high readings and low but overall the doctor wasn’t concerned. I’m no medical expert or anything but if your worried, it’s always best to speak to your doctor.