Hello please answer this?

hello well im 18 i got of the depo needle iv been off it for 6 months now and my periods have been normal except in october they were 2 weeks late i was due for em again on the 20th of november and they didn't come worried i took a HTP and it come back negative so i waited for em a week later i had spotting lasted for a day and was very light and that's it been haven pains in my tummy well not so much pain just really funny feelings so i took another test 2 days ago again negative wats going on ? can anyone give some insight no matter how small or big