But how are you sure that it is God telling you, and how can you be sure that you’re interpreting Him correctly? The mass proliferation of sects and contradictory teachings has occurred because so many people believed that God was telling them something.
I have gotten into this matter with Mormons many times. Most seem to believe that they can trust their own interpretation of spiritual experiences. They typically have a lot of trouble understanding that televangelists play off the same notions, and that every belief system that every man founded and led people astray with began with similar notions. It is a false formula to rely on one’s own interpretations of what one thinks God is saying to them, for it only creates confusion; it is essentially self-justification and belief in one’s own prideful foolishness.
Fortunately, God is much wiser than us and gave us many means by which to test our interpretations so that we could conform our will to His. The primary ones are the Church (Apostolic Authority, Tradition, Scripture); natural law (Creation), and history (of which God is the Author). This is why Jesus instituted the Catholic Church and solidly grounded it in all of these primary, external means of God’s Revelation to man. With these tools, we can know for certain whether our personal interpretation of how the Spirit speaks to us is correct. It requires our humility to accept that we may be wrong so that we may grow in insight and receptivity to the Spirit’s true meaning.
It wasn’t you who pointed to miracles in the LDS church or said that such gifts had ceased prior to the restoration. It was MEgus, and in my experience, many other Smithians.
(BTW, in case I haven’t said before, I use the term “Smithians” inclusively so that I can refer to those things that are common to the LDS, the CoC, Restoration, and Remnant branches that follow one version or another of Joseph Smith’s works. The only part of it that is indeed a little jab

is that I think it is more accurate to refer to these groups as following the belief system outlined by a specific man, since the earthly origin can be linked to him)
As for Satan performing “miracles,” I very much agree. He’s a great trickster. I have heard Smithians say that JS could not have been tricked by Satan because Satan would not have lead him to Christ. The problem with that is that Smith calls the other Christian churches the “Great and Abominable Church of Satan,” and they lead people to Christ. So obviously Satan very much enjoys spreading any lies that hurt our communion with God or cause contention among His children, even if we are all still striving to follow Him.
While Satan can perform “miracles” of sorts, I do not think he is responsible for all the “miracles” seen outside of one religion or another. I still think the Spirit works many miracles across humanity. I do think that the Spirit works most powerfully within the Catholic Church, though, particularly through the Sacraments.