Worst fears are happening

After the miscarriage in June and getting my bfp a week ago I started having mild cramps and back ache yesterday and then the light bleeding started .... it did stop last night and it’s just light pink and brown today but I tested again this morning and my positive is getting very faint so I’m guessing my body is rejecting this pregnancy as well.... anyone have two chemical pregnancy’s in a row and find out why? I go to the OB on Monday and will discuss this with him . I know I’m older (40) but my cycles are regular and I seem to not have a issue getting pregnant just can’t make it to 5-6 weeks ugh I’m heartbroken 😞