What could this mean?

So this is the second month where my period did not come on time but came like 30 days late when my following period was supposed to be due... before this my period was always regular, 28 day cycles lasting 7 days long. I had my daughter almost a year ago and we are trying for baby number 2. I have tested with the cheap test stripes and they are negative. Should I test with a different kind of test? Has this happened to anyone? I’m 26 days late currently