Depending on what's going on generally in our lives and with our moods it's easy to fall in, and out, of love with our significant others.
In saying I care about him a lot, he´s my best friend it's clear that you have something worth holding on to and it may be that rekindling the fire won't take a great deal of effort.
There was a recent thread where the OP was advised to go off with her DH for a day of extreme sport - white water rafting, bungee jumping, theme park scary rides or similar - because an adrenaline rush could well be all it needs to lift your relationship to another level.
As for the 'real big love' - as lachesis has said, it looks highly desirable on the big screen with soaring music and no need for the perfectly coiffed heroine to wash his dirty socks, put up with his farting and less than tasteful personal habits, sort out all the mundane aspects of life (budgeting and the daily grind), and stress about if she's losing her figure/mind etc plus, of course, it usually lasts for less than 2 hours.
Many thousands of women wish they hadn't been blinded by the fireworks and would give anything to have reliable, honest, dh that they could call their best friend.
Don't throw away what you've got just because you may be temporarily depressed and not thinking straight; all marriages have highs and lows - talk to your GP about your depression and start rekindling intimacy with your dh.