Could I be having a miscarriage

[starshell8411]

So my period was suppose to start this Saturday July 16 according to the app but I started spotting on the 12 dark brown and got lighter on the 13 until 14 when it started more heavily and needed a pad so basically I think my period came 4 days early but I've been having severe back pain and cramping and felt nauseated but the back pain is unbearable the bleeding isn't heavy like other months when it has been clots. No clots but heavy flow could I have been pregnant at first when the spotting started I thought it was implantation bleeding but then it got heavier and I just thought it was an early period. I did have intercourse w my partner on my ovulation day which was June 29 I was really hoping to conceive as I haven't been able to I'm 31 and we have been together 12 yrs and still nothing I've been putting off a check up to the Drs because if financial reasons but I know I'm due for a check up ASAP