Any idea what could be going on?

So on April 22 I had very light pink spotting it was in my discharge (I also had period cramps as well ) no more spotting The rest of that day so I thought maybe that was implantation bleeding cause we bedded in my ovulation window. So I took a test a couple days later and negative so I figured maybe my period is coming soon l. Than April 14th same thing happened but very brown this time and just in one wipe and nothing again the rest of the day. So I took another test April 16th and negative again. April 20 and 22 same thing again as April 14th. Than April 25 26 27 I had light brown spotting in one wipe again and nothing all day so I kinda just took the three days in a row with the spotting as an off period. Well now I’m 2 weeks late from my expected period. I’m on day 51 from what I thought May of been my period in April. I have taken many tests and all negative. I don’t feel pregnant but have the cramping like I did with both my boys in the first trimester. (It’s a different cramp compared to period cramps) I have a Dr appt next week as I have never had this ever happen to me. Just wondering if this has happened to anyone before and if you were actually pregnant but always getting negative tests. Thank!