yet another med

Hi guys I'm starting to get worried 
This is kinder not the best subject but bowels or lack of movement the doctor gave me some stuff 3 weeks ago as I have been in 4 weeks
Well I'm almost going on 5 weeks last week she gave me something new and said it would work in 48H it's been a week and still hasn't my ultrasound showed I'm very backed up I'm not hungry and I can no longer force myself to keep eating with out spewing it hurts round the clock and the more I try to go the more pain I'm in an hour later nothing 
Iv never been this constipated before I have a healthy diet of mostly fruit veg ect 
What else can I do I'm taking the stuff they doctor said she said next step will be a table where I don't want it but if haft to I haft to my main issue is not eating when pregnant with twins and the pains are driving me nuts