Confused.

Im not reallg sure what this post is. Kinda looking for answers, wanted to get my frustration out. See if anyone else has been through the same thing. Any sort of response would be appreciated.

This is going to be a long post!

To give you a bit of background.. I had the implant in for 4 years before me and my husband decided we wanted to try for a baby. I had my nexplanon implant removed on May the 9th. I didn't get a period till June 23rd. the length of my cycles are pretty much always 5days long. the next period after this was September 3rd, then October 27th and my last period was december 4th. my cycles have been getting shorter. 72 day, 54 days then 38 days. in November I had a positive OPK  on cycle day 28. I got my period 10 days after. this cycle I had a positive on cycle day 19. I'm currently 15DPO with no period and only BFN. (I may have got a very very faint line yesturday). according to glow I should have had my period 2 days ago. I also have Ovia which says my period should be due on 12th which would make it at 39 day cycle.

Should I have got a period by now? Is it normal to have a lutle phase of 18 days (going from Ovia app) could i be pregnant but still not getting a BFP at 15DPO (I know some people take longer) Should I wait to see if my period comes on the 12th? Should I see a doctor if it doesn't. Should I do another test on Friday if my period doesn't Come?