[Always *]

Just try to keep calm. You don't have to wait until you get your period, lots of people have irregular periods and don't know when they'll come. Just wait for 2 weeks from the event which is scaring you and then you can take a pregnancy test and find out. So it's ok
If it helps, I have this app called Period Tracker. You can down load it and track what day your period starts and ends, after 2-3 cycles it'll start being able to tell you how long each cycle was (right from time 1, say 1 is 28 days another is 34 and a last is 26), and how long you average cycle is (which needs a few cycles to calculate). It's a good app and might help you knowing when to generally expect your period even if it is irregular because at least you've kept track and got some averages. It's not going to help for this situation right now but it can be useful information to have should this be of interest to you.