25 day cycle

Rosie. • I`m 26 yrs old my husband is 28 we have been trying to conceive for 6 months 3 months after we had a miscarriage!
Me and my husband have been try to get pregnant for about 4 to 5 months now last month I had a 4 day period it's usually 7 days and 25 days later I'm having a light period really bad cramps and lower Back  pain what do you guys think?? I've also had a miscarriage about 7 months ago so it's a little scary!