Periods after methotrexate

I had an ectopic pregnancy and I was about 5w3d when I got methotrexate injection which was 9th november and then On 14th november I started bleeding and I passed something which was red and grey whitish, I know it was baby coz it was exactly like my previous miscarriage but the thing is I only bled for 2 days and then its been a month now I haven't started my periods yet...is it concerning? Do I need to go for check because last hcg draw after injection hcg was 18.