Talk to your doctor or healthcare professionals about your altered sense of smell. It can be a symptom. It might also be normal for 4 months or some period of time post pregnancy. You can get a better idea about whether it's a symptom or normal, or someplace in between by talking to them.

This page has a good outline of the sense of smell, and changes people usually have. Usually when people have a reportable symptom in that area, it's probably losing their sense of smell. But, an altered sensation in general can be a symptom of a problem that is worth checking out.

http://www.nidcd.nih.gov/health/pubs_st/smell.htm

In general smells are usually related to VOC's or volatile organic compounds. They can be as natural as those resulting from unfinished old wood which is acting as a growth medium for natural fungi; or the smells of citrus rinds. They can also be from man-made stuff which is more likely in the case of paints, or artificial added fragrances, or smells coming off of new foams. Some woods have pronounced odors even as the natural wood with or without adding fungi or finishes.

Odor problems can be complex. If you live in a humid climate, getting a whole house dehumidifier can be helpful to reduce even 'normal' levels of fungi. A whole house HEPA filtration system can filter out a lot of problematic particles. Experiment with products to find a laundry detergent or soap you can at least tolerate. That alone can add a lot to your quality of life. Go out of your way to seek fragrance-free or additive free products (that can usually reduce the overall incidence of imposing smells).

ask about VOC's when looking for art supplies or wood finishing products (even if products are all natural find out this information because even natural products have a characteristic odor which you might find to be objectionable)

P.S.If you need to impose changes on others, as to their perfume wearing or things like that, it can go over more easily if you refer to your 'acute sensitivity to fragrance.' The key is to make such requests based on your reality as much as possible, without using adjectives based on your perception of the fragrance involved. (Such perceptions are personal, and people will tend to take any criticism in the area of personal hygeine or fragrance routines personally; and probably will react badly.)

I had a heightened sense of smell especially with my first pregnancy. I felt like a labrador retriever. I remember getting grossed out that someone lit a cigarette and turning around only to see someone smoking over 100 feet away. I could walk through a crowded store during Christmas and tell you who was drinking and what kind of hair conditioner someone used. I still can't use Tide (DS is 5) - turns out my son is sensitive to it as well. I still can't stand the smell of Windex. I changed the selection of wallpaper that I had previously selected for our old new house because it made me sick. I couldn't even think of the house without throwing up because it smelled old - we were fixing it up. But thankfully fresh air smells good again and I can walk down the coffee isle. Anyway, I can't exactly remember how long it lasted but the disgust lingered after the pregnancy but not the nausea. I think part of it was just the memory and the association of being nauseous plus the new awareness of smell. Eventually I got over most of it.