Lactational Ammenorhea?

Hi guys. I have a 10.5 mo daughter and lately I've had what seems to be morning sickness, my nipples hurt while breastfeeding, I've had a few twingy cramps, I've been getting headaches, I've had lower back pain, had to pee more than normal, and I've been dizzy. Most of all I just feel like I'm pregnant.

However, I've taken 2 pregnancy tests in the last 2 weeks and both were negative. My main problem is I'm not sure when to test because I haven't had my period yet. Should I just wait a month and test again or...?

Thanks in advance.