Low Placenta

I'm currently in my 15 weeks, and had a recent check up cause I had been spotting. Doctor mentioned that it is due to low placenta which cause the spotting and it will be on and off throughout until the placenta moves up or something. Doctor gave me duphaston to eat. At times, I just can't help worrying as I had 2 prior miscarriage before this. Even though doctor says the chances of miscarriage is really low cause baby seems really healthy but I just can't help to worry. I'm still having on and off spotting and I've been feeling lethargic even though it is my second trimester. I stayed off from work during my entire first trimester and only returned to work recently. But I feel like I'm burdening everyone at work, cause it is very limited things that I can do. First trimester had a blood clot which sticks to the pregnancy sac so also had spotting till the blood clot dissolved. I feel like the pregnancy is stressing me out mentally more than physically. Just ranting to get things off my mind.