What would you do

Hi everyone just looking for as much advice as I can get with this. This is my cycle it looks like I got a surge at CD15/16 which was 4th and 5th March. Although not recognised but the app and the app predicted ovulation later. I know that a surge doesn’t mean that you will ovulate on those days. We BD on these days. A lovely girl offered advice on my previous post and said I should really be trying every 2/3rd day during fertile window. Is there any other advice I should take on board for next time? This was my first month trying to find the surge and thought I had did ok with it but obviously not as I got my period today which was 2 days later than usual. Does anyone take multi vitamins and find they help? We are currently taking the bus and hers pregnacare. A bit disheartened. Any help appreciated thank you.