Help! Extra long cycles 😰

Mine are usually around 40 days. Sometimes more sometimes less. The first day of my cycle is always extremely painful, resulting in vomiting and diarrhea with very heavy flow. Days 2-5 are normal. I take zofran to deal with the nausea but I'm allergic to NSAIDs. 
How long are your cycles? 
What are they like? 
What's the best way you've found to track ovulation with an irregular cycle?Â