If you get your period you're more than likely not pregnant. In some cases yes you can still get your period the first few months, but not often.
Most of the time you don't feel symptoms until 6 weeks. They are tiredness tender/sore breasts nausea with or without vomiting and missed period.
back pain or stomach pains can happen too. Lol but it looks like Makayla213 has told you the most common. And like she said if you get your period it is more likely you're not pregnant. The most accurate way to determine if you are would either be blood or ultra sound.
Some people have implantation bleeding, i did with my first two pregnancies and this can be passed off as a light period. I also had cramping like feeling my period was going to start but never did