Birth Control & Early Pregnancy Signs: What You Need to Know

Question
Hi again!  Thank you for taking the time to answer my question.  So if I am understanding you then since I have been on the pill so long it can change the results.  Then why do they tell you not to stop taking your birth control unless you are positive on being pregnant? Because the only way to know for sure is then through blood work.  Right?  I made a doctors appointment for today because Thursday I started to spot bleed, it is very light but it is there.  I have also been getting shotting pain in my breast.  So I am going to get checked out.  Thank you for your time and help!
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Followup To
Question -
can taking the pill alter the results of a pregnancy test?  I have been on birth control for three years and just one month ago I took a whole month off for some test I need done, among those test was a pregnancy test that came back negative.  I feel that during that month though I did get pregnant.  Within the last two week I have been very emotional, tender breast that have grown a lot, always tired, and very neausa over everything all day.  I also had a light period.  I took a test a couple of day ago that came back negative, but could my birth control alter that result?  I really need help with this.  If you can not help can you please let me know who could...I hoping to hear something back...Thank you!
Answer -
Normally when you have been on birth control for awhile it may take some time for your body to get back into gear after stopping use but it is never permanent.  Your body ofcourse has to get use to producing its own hormones once again.  This can take up to 1 week or even up to a month.  You may be pregnant as you do show symptoms but it could also be from the changing hormones in your body.  Try testing again in a few weeks to make sure but I am thinking it could be a false alarm.  

Answer
"Then why do they tell you not to stop taking your birth control unless you are positive on being pregnant?? " - Women's bodies are all different.  It can take 1 person a week to get back to normal and it can take another 3 or 4 weeks. Most of the time it doesnt affect pregnancy tests but every now and then it can, and that is why.  Good luck with your appointment!