Here's why I think Bernie still has a chance: Things get better for him from March 22nd on, according to aggregate polling taken from this website:
Bernie Sanders Doesn?t Need Momentum ? He Needs To Win These States | FiveThirtyEight
Now granted, he's performed better that expected in certain states and worse in others, for example Massachusetts (which he lost by a close margin - a Warren endorsement would have sealed a win for him there), but
more time = more exposure. People already know Clinton, so when states like Kansas have a lot of undecided voters, and they find out more about his policies (thanks to canvassing and phonebanking), they win him the state. Nobody knew enough about Nebraska and Kansas' polls to be certain of who would win, and he won both by a significant margin, including Maine's caucus yesterday.
Unfortunately despite winning 3/4 of the states this weekend, he only won the total delegate count for those states by about 3 (Louisiana has a lot more delegates overall), and it looks like he might lose Michigan tomorrow by a sizable margin, depending on how much the recent surge in phonebanking/canvassing in MI has helped.
Unfortunately the mainstream media also plays a huge part in how much exposure he's getting, and when they do mention him they're generally pretty dismissive. Just today CNN was talking about how Hillary would beat Trump in the general, but get beaten by Rubio and Cruz - all while they briefly show a graphic of how Bernie beats all of them by a comfortable margin, without actually mentioning him once. A clever tactic for people who just turn on the TV to listen to in the background.
But to put things into perspective a little bit, Hillary currently has about 28% of the delegates needed to win the primary, while Bernie has 20%. How does that show that she's already sealed the victory? And like I said, considering that things pick up for him from the 22nd on, he still has a decent chance of catching up. It's an uphill battle, but don't give up hope Chemdaaa!!