I had gallbladder surgery 6 days ago and I still haven't had a bm. Is there a laxative or something I can take? My stomach is sooo bloated.

Try. First to induce a bm by either using a suppository or a small fleet enema (sodium bisphosphate). Do not use laxative through your mouth without contacting your surgeon. You may need to be examined by him as there are several possibilities fecal impaction being one of them. So if unsuccessful in your attempts call the surgeon tmro morning!
Yes. Drink more liquids & eat smaller amounts of solid foods. Decrease the amount of narcotic pain medication you are using or stop them. Go to the drug store & ask pharmacist. Can try milk of magnesia, miralax, (polyethylene glycol) magnesium citrate, etc. If you are also having vomiting or fever then contact your surgeon.