Pain in lower abdomen and lower back but no period?

Normally the only time I have pain in my lower abdomen is when I’m on my period or pregnant. I gave birth 5 months ago and since then I have been spotting between periods and Now I’m experiencing pain in my lower abdomen and lower back. It’s not ovulation because ovulation pain is different for me I only have pain on one side and this pain is not like that it’s my whole lower abdomen and it’s really painful 😣 I’m not even due for my period and I just recently stopped spotting a couple of days ago. I set up an appointment with my gyn but it’s not until June. What is causing this?? I’m definitely not pregnant could this be cancer? 😰