welcome to HCM.
You are TTC for last 5 yrs and regular cycle with 26 days. Also you are taking Meprate
10 mg twice daily from 20th day for 7days and you got negative pregnancy
test on 31st day.
Meprate has some side effect like early or delaying period,inter menstrual bleeding
etc.So you have to aware of that.
Early pregnancy test result may be negative.So repeat the test after 7 days of missed period.You can do a fresh USG for confirmation of pregnancy and evaluation of underlying pelvic pathology.
Consult with your doctor for evaluation and cause of long time infertility
Do light exercise, take healthy diet, avoid stress and sleep properly.