Advice please!

So my wife and I did a home inseminaton with a known doner. We did the inseminaton on May 9, 11, 12, and 13 and the 14. And I was supposed to start my period on 5/25 and I still haven't had it. My last period was April 29. I've taken multiple pregnancy tests and they've all came out negative! The last test I took was yesterday and it came out negative. I have been having some cramping not like period cramps, I get those in my back these ones are in the front in my lower abdomen, nausea, seems I'm always going pee, irritable, and I'm always tired. Could I be pregnant and when should I try and test again? Everyone I talked to said that I should go into the clinic and get a blood test to see if I'm pregnant and maybe the hormones aren't strong enough to detect on the hpt   I need some advice.