Maybe yes and maybe no. Did you use the first morning urine when you did the test? It is the most concentrated sample and thus provides the most accurate results. It is also not unheard of for women to have negative tests even when they are several months pregnant. So, there is a chance you are pregnant.
However, it is also possible that things like stress, illness, medications, or changes in diet are to blame. Your age is listed at 43. It could be that you are entering menopause.
I would have the doctor do a blood test since they are more accurate than the urine ones. S/he can also do blood work to check your hormone levels and see if you are entering menopause and also check for other things that could be causing this.
yes better take a blood test that will be more accurate to know are you pregnant or not,and sometimes periods gets irregular too.