so here I am with a track that sounds really good, energy wise (I start with the arrangement).
but when I started working on the bass I've noticed it doesn't feel right.
since then (3 days) I tried all the bass pattern I know.
I tried a bass that will fit the drums - doesn't fit the lead.
I tried a bass that fit with the lead - doesn't go well with the drums.
I tried something that go well with both - and it doesn't fit the pad that have a major roll.
the chords (pad) change in rhythm so in the second bar there are two chords for half a bar each.
same for the fourth bar.
maybe that's the problem, but I'm sure there is a bass that can accompany it and stay with the entire track.
I can just copy the melody pattern and play with it, but its making the track sound very thin.
any advise will be much appreciated!

The best solution would to be listen to all parts together and play a new bassline on the keyboard. If you don't have keyboard skills, don't worry, just tap out the rhythm of the bassline on one note and change the pitches in the sequencer afterwards.

If the track is busy, the bassline might have to be sparse but that is not a bad thing.