advice please

so my husband and I have been ttc for about 5 months now. the first 4 months we didn't track ovulation just went by what the app said. this last month we tracked ovulation and used conceive plus. since about 3-4 dpo I've been having light/dull cramping in my lower abdomen area, tender breast up close to my armpit, and have been extremely sleepy for about a week. I am not 4 days before my period and I tested this morning and got a BFN. anyone else have this issue ?? just dont know if I should assume I'm not pregnant & try again next month. I did order a bbt, and its arriving tomorrow, i ordered it in case I didn't conceive this month.