I find a bit of booze before I start tripping helps a lot. I have problems too with mushrooms, I always hated the depressed thoughts, and the anxiety on them. I find if I get a nice buzz on before I trip, the trip is a lot more easy going.
Another option is to maybe not eat as much? Personally I have an extremely low tolerance to psychedelics. I found I actually tripped too hard off of a single gram of mushrooms, so I tried eating 0.5g and I didn't get too high. After a lot of trial & error I discovered that 0.75g of mushrooms was actually the perfect amount for me. I found on one gram of mushrooms I was really nervous and felt like I was out of breath the entire time, but taking away 0.25g actually did a whole lot. I obviously wasn't as high as one gram but it was still enjoyable and I didn't have many negative side effects (they weren't nearly as noticable)
One more option, is doing E with Mushrooms. Obviously you're going to get extremely fucked up, however, but it really got rid of the depressing thoughts and anxiety. If you enjoy getting extremely high, I'd give this a shot, honestly. But you need to be ready for the horrible come-down.
Also, I found E and Mushrooms really brought out the psychedelic thought processes, which I really love. It made it a lot more enjoyable and seriously opened my mind to things.
Obviously you could replace the liquor with weed, but personally I don't enjoy smoking weed on mushrooms - it gets me WAY too high. It's all personal preference, really.
One more thing, if you do plan on mixing drugs make sure to be extra safe (sorry I'm not trying to lecture you, I just care about the well-being of other people)! Make sure to stay hydrated if you're mixing Mushrooms & Ecstasy! I find sometimes the mushrooms makes me forget to stay hydrated and keep a good body temperature, so you need to be extra cautious about this stuff.