Well I’m on a 28 day cycle and I haven’t had a period since December 25th well my app says I was supposed to start yesterday but if you count 28 days from the 25th I should’ve started on the 22nd for the past week and last week I’ve been getting nauseous but not throwing up this week I’ve been getting a lot of headaches and now i have a migraine and my stomach hasn’t been feeling right and I haven’t been spotting or nothing . Could i be pregnant and how much longer should I wait to take one ?