Okay so I have a relatively normal cycle (about 30 days).. until this month. Right now I am going on 45 days since my last period. I have taken at home pregnancy tests and all come back very clearly negative meaning I am not pregnant but I am sexually active, could I still be pregnant? In the last few weeks I have felt very emotionally touchy and cry at almost everything.

I haven't changed anything in my daily routines and I am not stressed so I cannot understand why I am so late on my period. I have been having cramps and lower back pains as if I was going to start my period but no period at all.. and no tender breasts as usual near my period. Can someone give me some insight on this? Please keep in mind a period this late is NOT normal for me. My periods are normally right on time, maybe a day or two late or early.

Missing a period here and there is not that uncommon, mostly it's usually due to stress, diet changes, weight loss... if you miss two periods consecutively that's when you should start to worry (but don't worry too much!! )
On the other hand, yes it is still possible that you could be pregnant. Sometimes women's hormones don't rise enough for an in home pregnancy test to be able to detect it.

The best thing to do would be to see your doctor and have a proper pregnancy test and physical exam performed. They can see if you're pregnant and make sure there's nothing wrong!

Good luck!