Kinda confused

So I use 2 ovulation Calender's. One being mydays (which I've had since October) and then of course glow. My period was funky this month because it came so late. Now I'm getting 2 different ovulation dates :/ glow said last week and mydays says the week before last. What do I go by? I had sex both weeks to be safe but I feel awful right now. For days my breasts have hurt like crazy and I'm nauseous beyond belief. I'm not supposed to start my period until at least the 7th. Help?