Let me suggest a low-tech way to solve your. If you have a small room, you should have no problem experimenting with things you have on hand to see if they help your problem. Blankets, heavy coats, pillows, cushions, all of that can be tried at no cost and no commitment, and no measurements other than your own listening. You can cover up big, flat, hard surfaces, but you can also start with the mirror trick. Temporarily stick a mirror to your wall, moving it around so you can see a reflection of your speaker(s) in it from your listening position. When you find that position, put a chunk of fuzz there. You'll usually find those spots on at least 3 walls, possibly 4, and the ceiling if you try it. Fuzzing those spots takes care of the largest and most prominent reflections. Listen to the result, see what you think, then make those temporary test positions more permanent by placing absorbing panels there. This won't deal with the low end, but from what you say, it may just take care of your problems.
You can't use studio mics for reliable acoustic measurements. Taking useful acoustic measurements you face several hurdles, one of which is a good test mic, and preamp. Then, learning how to operate the software, then interpreting the resulting data. The first two are easy, interpretation not as much.
You can get 80% or more of the way to your solution using my low-tech method.