Confused? Baby dodgy tummy, don't know why?

Not sure what the problem is?
My baby boy was a prem 2 months early, so has has occasional gastro issues.
I have breastfed him and continue to do so, apart from a top up bottle on an evening of formula.
I introduced solids about 3 weeks ago, starting with baby rice and pureed fruit (mainly apple, pear or mango).
I then introduced other food, some from Heinz/rafferty's garden range for 4 month old (I know, I am going to do home cooked food, just didn't have the time, at that point). All seemed ok for a few days.
Then he got diarrhea, at least 5 times a day, terrible nappy rash, green poo and it's mucousy too. He sometimes seems uncomfortable with his tummy, has terrible wind and fusses while feeding.
He has now had diarrhea for 2 weeks and it's getting worse.
I have taken his solid food right back too baby rice again but still no change.
I took him to dr's today, dr thought it could be a virus (what 2 weeks worth???). He wants me to take a stool sample in.
I mentioned I was concerned it was a Lactose intolerance, dr wouldn't entertain the idea. I am also worried it could be an allergy.

Not sure what to do next????

Anyone throw any light on the situation?

Thanks.

Poor baby!
Not lactose intolerance at this age (would be from birth or school-age-ish), though 2ndary LI is possible as a result of the diarohea (I can never spell that word). If so, that would sort itself out once his tummy is better.
Is your topup formula dairy based? If so, and this is a new problem, then unliekly to be dairy allergy I guess. If it started with the introduction of new foods, then it could well be some other allergy - which has had knockon effects lasting this long... maybe?
Viruses can certainly have this effect, also. Maybe get the sample done and see what that can tell you?

Yeah thanks MadB, using S26 formula for the top up, and have been for about 3 months (just so I can do my doula work and jet of at a moments notice). So guess it isn't a dairy allergy. Feel guilty for using the Heinz jars and Rafferty's now. Going to get sorted and cook up some batches of veggies I think. At least it will be easier to find out if any one item of food is causing the problems.

I agree, not a dairy issue. My son has a milk protein allergy and he reacts when I eat anything dairy and it comes through in my milk. Sounds like you have a good plan to see if one of the food items is disagreeing with him.

Don't feel guilty for most babies won't react badly to the prepared food. I"m the only person IRL that I know with an allergy baby and having to introduce one food slowly at a time to test for a reaction. Everyone else is feeding their bub this and that without worrying too much.

Hopefully the problem will be sorted soon and I hope the reaction doesn't last too long.

Sounds like your doctor is on the right track - sounds like gastro. Hoefully it will be a lot better soon