My body is gaslighting me

I’m new to this subreddit but it feels like a safe space to vent a little. I’m 40 and TTC baby number 3 to complete our little family. Whilst 3 has always been our dream, we agreed to give it until Christmas and if nothing happens, then we plan to stop actively trying happy that we already blessed with our 2. This is cycle 2 and I’m under no illusion that at 40 the chances are slimmer than before and know a lot of symptoms can also be PMS, however I really do feel gaslit by my body this month. I’m 5 days late (never happened before) and have symptoms I never usually have with PMS. I have heartburn, gas, low grade nausea (last night I threw up before bed), a complete loss of appetite and real low down crampy feelings on and off since about dpo day 8. But I’m testing negative, so am not pregnant. I’ve had a tiny bit of brown spotting - I assumed it was my period coming and was happy to be able to start a new cycle and relax but nearly two days later nothings happening. It’s just frustrating feeling like this and waiting for my period to hurry up! I’m sure a lot of you feel the same. Thanks for letting me vent x