You need to follow the instructions on the packet for home testing and don't test too early. The instruction on the packet will say how many days after a missed period a test would be more accurate.
You can also get the symptoms you have from a hormonal imbalance, and around 10 days before a period until your period starts. This is called premenstrual tension (PMT) sometimes called premenstrual syndrome (PMS).
How many days late are you to having your normal period? This will help to establish whether you took the pregnancy test at the wrong time.
If you period does not come within the day or so and you are very late for your period, make an appointment to see your doctor to get a blood test taken to check for any hormonal imbalance and whether you are pregnant or not.
If you start to feel like you want to puke, then that would indicate a pregnancy.
Sometimes the home pregnacy test will not pic up the hormons to give a positive reading. Some woman need blood test to know if they are pregnant. Sounds like you MIGHT be. Blood test will tell you for sure. Gd luck. Hope my advice helps.