According to Medical1Stop.com, tiredness is by far one of the most obvious symptoms of a pregnancy, especially if you sleep enough and you do not engage into any exhausting activities. Tiredness often comes with a general state of weakness. Levels of progesterone grow automatically when you get pregnant. The high hormonal levels ask for extra rest, which means that you feel like sleeping a lot more. Other than that, the low blood sugar will also add to your energy loss throughout the day. Arterial hypertension may also kick in if you are sensitive. Things like these make some of the most obvious signs of a pregnancy.