Feeling confused... need some advice!

Ok ladies, I have tracked my periods for about a year and a half now. Cycle averages about 31-35 days with 7 days being my period (according to my app calculations which predicts ovulation/period based on previous) October and November 2017 I bled from the 1st-7th. December 2017 rolls around and I started the 7th-12th. I then bled again December 27th, 2017 until January 4th, 2018! Bit shocking having bleeding just 20 days later for a longer period of time, was also a tad bit heavier flow than normal. January has come and gone with no period, on day 39 now, but the week of jan 7th (expected to ovulate that week according to app) I did have unprotected sex. The following week I had UTI symptoms and then the next week (about 2 weeks after sex) started with symptoms including nausea, vomiting (thought that was the stomach bug), increased breast tenderness/sensitivity, back ache, sweet and salty cravings, fatigue, basically what everyone calls “pregnancy symptoms”. (Side note: I am happily married and already a momma to an almost 4 year old handsome little man so I am well aware of pregnancy symptoms) I never experience PMS symptoms so for me to have multiple symptoms this cycle is confusing enough! I have tested, BFN (big fat negative) on 3 tests!! Tested two days before expected period on Jan 28th bc of my symptoms, then tested Feb 1st (morning urine) and Feb 2nd (mid day urine). Negative, negative, negative. What do you ladies think?? I can’t remember how soon after I tested with my first and got a positive :/ anyone have similar experience and ended up with a positive after multiple negatives?!?