I have bowl problems pls advice?!

Im looking for pro advice on this matter im 27 and seen my doctor twice for this...ok i seem to be having issues pooing sometimes i can go a week without pooing but i get very bloated and suffer tummy ache when this happen i poo about 5 times before having very painfull dioreah. After thats happened sometimes i start to go back to normal but at the min after the dioreah its been 3days and iv still not gone again it makes me feel sick etc. When i do try to go i have to push very hard and sometimes it comes out like rabbit poo in bits but very hard. All i got from the doctor is it sonds like IBS (iritable bowl syndrome). Is this right or whats wrong i am on meds ill name them.... Lansoprazole,prochlorperazine,co-codamol… advance. All of these are prescribed to me please help can any of them cause problems i take lansoprazole every day and co-codamol.