HELP 😩

Hey girls we had protected sex on 9th sep.. i got my periods on 23rd (on my due date) but they were so light and i was tensed so i took pregnancy test ( beta HCG) the result was less then 2. But now i have severe constipation , back pain and mood swings 🙄😩. Can you guys plz help me out? Im so tensed right now.