So my husband and I are trying to conceive baby number 2.  I have an 18 month old son, and I've been off BC since March of this year.  My cycles were anywhere from 28-31 days long for about 4 months or so but by June they had settled into a fairly consistent 30 day cycle.  We started trying in August and when day 30 rolled around my period didn't come.  I waited and tested and and waited and tested some more but all hpts were negative.  I began feeling symptoms like occasionally nausea, tingles in my breasts, etc.  On cycle day 40 I took a first response early result test and there was this super faint line.  It was very faint but it was there without having to squint or anything, but I was still really suspicious of it because with my first pregnancy the line was darker.  Anyway  because I wasn't convinced by the test I took another first response the next morning and it was negative.  Four days later my period started.  

The next cycle I had was in September and due to a family emergency my husband and I weren't able to really try so I didn't think we had a shot that month and I was right.  My cycle came on day 30 exactly, just like usual.  

Now I'm on cycle number 3 and I am again almost two weeks late (cycle day 43 now) with negative pregnancy tests (first signal from Walmart).  Today my lower back started hurting which usually signals an impending period, so I'm waiting on that now.  I don't know what is going on.  I'm naturally a stressed type of person, so I really don't feel any more stress about trying to conceive than I do about any other particular thing.  Plus last month was much more stressful and my period came right on time anyway.  I just wonder if anyone had any similar experiences.  Is it possible that I'm having chemical pregnancies where they just don't "take?"  I feel like I have to be ovulating since the cycles do keep starting over, and with the first cycle I felt a lot of symptoms (this cycle not very many except for breast tenderness and fatigue).  Has anyone had this happen and then were able to conceive later without help?  I'm thinking I need to go to the  doctor and see what's going on.  I do have hypothyroidism but it was checked over the summer and was fine.  

Also just a bit more information.  Prior to having my son my cycles were highly irregular and my thyroid was messed up.  Once that was fixed and I went on clomid I got pregnant after third round.  But they had a hard time figuring my conception date due to those wonky cycles.  The hpt didn't show positive until late, which gave me hope until this cycle where it feels like it's happening all over again.  

I'm rambling now I fear.  I'm sorry for the lengthy post.  I would appreciate any insights from anyone who has been through a similar experience.