Call a Lactation Specialist, to get a professional opinion, I"m sure they deal with this all the time.
each woman is different... some have no problem and some do.
I would pump more often if you are able to. And perhaps consider what to do if you get engorged... for which pumping will help.
Feed baby as often as you can, when you get back.
DOES your baby take a bottle? Have you tried? If he does not... then, how will he be fed?
Consider all situations, and then a solution to it.
Also, if your supply is not back in full force when you get home... how will it be regained? Ask the Lactation Specialist this too. Perhaps, have in stock some Fenugreek and Mother's Milk tea, just in case, when you get home. So you are already prepared.
Each baby is different... and whoever is caring for him, must feed him on demand, since he is so young. 3 months old is typically a 'growth spurt' time....and he may need to feed more. NOT on a schedule. Consider that.
When you pump, try to pump both breasts until it is drained. Thus, your breasts, in theory, will produce more, or keep producing.
Then, consider what you will do with the pumped milk on your trip... toss it or store it? Thus, needing to have (on your trip) extra milk storage containers and a refrigerator/freezer or cooler with you in order to transport it all home with you. AND, if going by airplane... make sure you know the 'rules' for transporting stored breastmilk... I think there are rules/regulations on 'bodily fluids'?
Here is a link:
http://www.tsa.gov/travelers/airtravel/children/formula.shtm
All the best, just some thoughts,
Susan