Help & Advice please

Ok so I've not had a period since the 15th Feb! I've taken numerous tests all showing a BFN I did have slightly longer cycles than normal they are normally every 38-41 days but now it's CD74! I'm trying not to stress out about things cos that can also result in no AF! My boobs have been hurting for the past 2 weeks and have felt bloated, cramping and sore lower back, hot flushes, quesy and diarrhoea but still no AF. I'm going to book an appointment with my GP next week to get advice, just wondering if any of you have ever experienced something similar and if so what did you do and what was the outcome?