When should I see the doctor?

I normally have a 26 day cycle and I am now on day 34 with no period. I have symptoms that come and go such as tender boobs, slight nausea and a weird tugging in my lower abs. I get light cramps off and on and I keep thinking I'm going to start but then it's just watery discharge. Yesterday I had very stretchy discharge but only that day.
I really don't think I'm pregnant but AF hasn't come yet! I had a negative test at day 32 and I'm going to test again tomorrow morning. If I keep getting negative texts and AF doesn't come, when should I see a doctor??
Thank you for any suggestions you have!