Ob-Gyn questions? Ask a gynecologist online.
If your periods are generally 30-35 days apart, then you got your periods this month on more or less on the due date. This rules out the chances of a miscarriage. A heavy period can be due to the slight 1-2 days delay in your period.
I am sorry to inform you that there is very little chance of a pregnancy this month.
At 38 years, ovulation can start to get a little irregular. Since you would like to conceive, please consult a fertility expert for complete checkup and required tests and treatment.
If the spotting is very light, then this could be an implantation bleeding. Thee pregnancy test may not come positive during an implantation but may become positive about 7-10 days later. Although implantation bleeding generally clears up spontaneously in about 3-5 days, in some cases, it can continue for quite some time.
Please repeat the pregnancy test after another week. If it is negative, please consult a doctor for an ultrasound.