OK .....you added 5.95lbs of grain. Your first infusion was 1.84 gallons, and your sparge was 2.64 gallons. With 70 to 75% eff. your abv could have been 4-4.5% for your grain bill. The temps you listed were right in the range they need to be.
Here are the questions.....are the temps you listed actual temps of the grain bed after you added the water, or is that the temp of the water prior to adding the grain? You can go lower on the first infusion temp, personally I've mashed as low as 145. With the low side of the temp spectrum you make more alcohol, but have thinner beer.
Have you tested your Mash tun to see how long it holds temp?
What size is your mash tun? (re headspace)
What was the temp of your grain bed prior to adding your first water?
Do you have your water profile? Did you add anything to it prior to mashing?
(I.e. campden, bicarb, salt, gypsum etc)
Lastly, who crushed your grain? Was it the local HBS or did you do it?
If you did it what do you have your mill set at.
Crush is usually the biggest cause of poor eff, and the one variable I would check first. When I first started brewing, and the hbs ground my grain, I couldn't get out of the 60's. After switching to milling my own I have much better control over my crush. I gap my mill to put me in the high 70's because I like the mouthfeel at that level....but you can easily get in the 80's.
Next......I have to ask
.....but do you have a mash paddle, and are you using it?
