Go to your doctor. You should be able to see a dietician, but they are, like everything else, few and far between. If not, ask if the doctor can take you through an elimination diet. It's a bit of a pain (not physically) but will tell you if it's the lactose or if you need to look at something else.
Don't try and guess. You could be intolerant to something different or other things too. Once you know, you can come back on, and I and others can point you at those lactose-free things that have a reasonable taste.
I am just going on your thoughts about lactose, but it might be worth first asking the doctor if you might have IBS. If you have, and he/she is up to date, you should get help to use an elimination diet to find out which fermentable sugars you can't tolerate. Lactose is a fermentable sugar. If you want more information on this, look up FODMAPs. Monash University in Australia is the place that did the research for this, so it's worth looking there. Again, push for help from a dietician if you can. PM me if you feel I could help - but go to the doctor