confused

Savannah

july i had my normal period (5 days long) 2 days after my period i was spotting. 12 days after my period ended i had another period lasted 5 days. Then 18 days later again im on my period this time its been 7 days on my period. 3 days i was very light then 3 days was very heavy and 7th day im spotting....can anyone please help and should i take a pregnancy test?