Confused !!

Hi! I am 17 dpo & on my 6th missed day of my period. I have been taking tests and I feel like I see lines but also feel like my eyes are playing tricks on me. I've posted them in another group meant for faint lines... but haven't gotten much help. I just want to know how to make any sense on this. Why am I almost a full period missed but don't have a clear pregnancy test? I have all of the symptoms that I've never felt before. Tender breasts, sore nipples, super tired by like 7pm, morning & night nausea... etc. if anyone has any advice please let me know!