If your hormones are out of balance it isn't unusual to have bleeding after intercourse. Your cervix may be soft and sensitive and the act would irritate it and cause spotting. Nothing to worry about.
Hello, so so sorry for your loss. You said that you're on birth control pills to regulate your cycle ? From what I remember when I was on the pill years ago - was told my periods will be irregular as body adjusts to the hormones. Same thing when I went off them. However , talk to your doctor because I'm no expert. Good luck to you - I hope your heart and your body heal soon.