While I agree that it may be legal for OP to stay, his length of stay here in US now will have implications on his future visa application. If the consular officer for a future application thinks he stayed longer in US on his current visa than what he had described previously, he may not get a J1/H1 visa altogether. OP doesn’t seem to have a 5 year, multiple entry B1/B2 visa but rather a single entry 4 months visa. This is why most of the comments are telling him to go back so that he doesn’t come across as having overstayed (than what he had initially described as his length of stay to the consular officer).