late period

my last period was December 8th-14th I do tend to have an irregular cycle. so after being late I changed my cycle length to a 45 day cycle well its now January 25th and I still have yet to get my period. I am 7 days late from the 45 day cycle. I've taken 4 test all negative the only symptoms I have hare super sensitive nips to the touch!!! And I'm super tired. Idk if I could still possibly be pregnant or if my body just sucks and my period is just going to be completly absent this month. I've gone before with missing months but never had symptoms.